Psycholinguistics/Hemispheric Lateralization of Language

ontents

• 1 Introduction
• 2 The History of Discoveries
  • 2.1 Jean Baptiste Bouillaud and Simon Alexandre Ernest Aubertin
  • 2.2 Paul Broca
  • 2.3 Carl Wernicke
• 3 Methods of Assessing Lateralization
  • 3.1 Lesion Studies
  • 3.2 Split Brain Studies
  • 3.3 Wada test
  • 3.4 Functional transcranial Doppler ultrasonography
  • 3.5 Electrical stimulation, TMS and Imaging
• 4 Cerebral Dominance: Language Functions of The Left and Right Hemispheres
• 5 Anatomical Asymmetries
• 6 Proposed Correlations
  • 6.1 Handedness
  • 6.2 Sex Differences
  • 6.3 Sign Language and Bilingualism
  • 6.4 Culture and Language Lateralization
• 7 Reorganization following brain injury
• 8 Learning Exercise: 8 Questions on Hemispheric Language Lateralization
• 9 References

Introduction

Hemispheric lateralization refers to the distinction between functions of the right and left hemispheres of the brain. If one hemisphere is more heavily involved in a specific function, it is often referred to as being dominant (Bear et al., 2007). Lateralization is of interest with regards to language, as it is believed that language is a heavily lateralized function: certain aspects of language are found to be localized in the left hemisphere, while others are found in the right, with the left hemisphere most often dominant. This was initially proposed by early lesion-deficit models and studies with split-brain patients, and has been shown in more recent years through tests like the Wada test and imaging studies. There have been studies which show that there are anatomic asymmetries located near and around the regions associated with language, and each hemisphere has shown to play its own but separate role in the production and comprehension of speech. The hemispheric lateralization of language functions has been suggested to be associated with both handedness, sex, bilingualism, sign-language, and a variance amongst cultures. It has also been proposed that a reorganization occurs following brain injury that involves a shifting of lateralized function, as long as the injury occurs early in life.

The History of Discoveries

Jean Baptiste Bouillaud and Simon Alexandre Ernest Aubertin

French physician Jean Baptiste Bouillaud (1796-1881) was one of the earliest proponents of hemispheric language lateralization. On February 21, 1825, Bouillaud presented a paper to the Royal Academy of Medicine in France which suggested that, because so many human tasks are performed using the right hand (such as writing), the left hemisphere might be the in control of that hand. This observation implies that language, at the core of writing, would be localized in the left hemisphere. It was already known at this time that motor function was primarily controlled by the hemisphere ipsilateral to the side of the body through lesion studies. Bouillaud also proposed that speech is localized in the frontal lobes, a theory that was carried on by Bouillaud’s son-in-law Simon Alexandre Ernest Aubertin (1825-1893), who went on to work with famed French neurologist Paul Broca in 1861. Together, Aubertin and Broca examined a patient with a left frontal lobe lesion who had lost nearly all ability to speak; this case and several others similar to it became the basis behind the earliest theories of language lateralization.

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Paul Broca, image obtained from Clower, W. T., Finger, S. (2001)

Paul Broca

French neurologist Paul Broca (1824-1880) is often credited as being the first to expound upon this theory of language lateralization. In 1861, a 51-year-old patient named Leborgne came to Broca; Leborgne was almost completely unable to speak and suffered from cellulitis of the right leg. Leborgne was able to comprehend language but was mostly unable to produce it. He responded to almost everything with the word “tan” and thus came to be known as Tan. Broca theorized that Tan must have a lesion of the left frontal lobe, and this theory was confirmed in autopsy when Tan died later that year (Bear et al., 2007). In 1863, Broca published a paper in which he described eight cases of patients with damage to the left frontal lobe, all of whom had lost their ability to produce language, and included evidence of right frontal lesions having little effect on articulate speech (Bear et al., 2007). These findings led Broca to propose, in 1864, that the expression of language is controlled by a specific hemisphere, most often the left (Bear et al., 2007). “On parle avec l’hemisphere gauche,” Broca concluded (Purves et al., 2008)- we speak with the left hemisphere.

Carl Wernicke

German anatomist Carl Wernicke (1848-1904) is also known as an early supporter of the theory of language lateralization. In 1874, Wernicke found an area in the temporal lobe of the left hemisphere, distinct from that which Broca had described, which disrupted language capabilities (Bear et al., 2007). He then went on to provide the earliest map of left hemisphere language organization and processing.

Methods of Assessing Lateralization

Lesion Studies

A good deal of what we know about language lateralization comes from studying the loss of language abilities following brain injury (Bear et al., 2007). Aphasia, the partial or complete loss of language abilities occurring after brain damage, is the source of much of the information on this subject (Bear et al., 2007). As shown in the studies of Bouillaud, Aubertin, Broca and Wernicke described above, lesion studies combined with autopsy reports can tell us a a lot about the localization of language, which ultimately has supplied information on lateralization. Lesion studies have shown that, not only is the left cerebral hemisphere most often dominant for language, but also that the right hemisphere generally is not, as lesions in the right hemisphere rarely disturb speech and language function (Bear et al., 2007).

The dangers of using lesion studies are, of course, that they may overemphasize the relevance of particular localized areas and their associated functions. The connection between brain regions and behaviours is not always simple, and is often based on a larger network of connections. This is shown in the fact that the severity of an individual’s aphasia is often related to the amount of tissue damaged around the lesion itself (Bear et al., 2007). It is also known that there is a difference in the severity of the deficit depending on whether the area was removed surgically, or was caused by stroke. This is the case because strokes affect both the cortex and the subcortical structures; this is due to the location of the middle cerebral artery, which supplies blood to the areas associated with language, as well as involvement of the basal ganglia, and is often the cause of stroke. As such, surgically produced lesions tend to have milder effects than those resulting from stroke (Bear et al., 2007).

File:Splitbrain.jpg

An example of a study involving language in a split-brain patient. The individual says he does not see anything, because the dominant left hemisphere cannot "speak". Image obtained from Experiment Module: What Split Brains Tell Us About Language

Split Brain Studies

Studies of patients who have had commissurotomies (split-brain patients) have provided significant information about language lateralization. Commissurotomy is a surgical procedure in which the hemispheres are disconnected by cutting the corpus callosum, the massive bundle of 200 million axons connecting the right and left hemisphere (Bear et al., 2007). Following this procedure, almost all communication between the hemispheres is lost, and each hemisphere then acts independently of the other. What is striking about split-brain patients with regards to the study of language lateralization is that a word may be presented to the right hemisphere of a patient whose left hemisphere is dominant, and when the patient is asked to name the word they will say that nothing is there. This is because, although the right hemisphere “saw” the word, it is the left hemisphere which “speaks.” If that same word is presented to the left hemisphere, the patient is able to verbalize the response (Bear et al., 2007). As such, split-brain patients have presented substantial evidence that language function is generally lateralized in the left hemisphere.

Wada test

The Wada test was created by Juhn Wada at the Montreal Neurological Institute in 1949, and was designed specifically to study lateralization. A fast-acting barbiturate such as sodium amytal is injected into the carotid artery on one side (although current procedures prefer to use a catheter which is inserted into the femoral artery), and is then transported to the cerebral hemisphere on the opposite side. It then serves to anaesthetize that side of the brain for approximately 10 minutes, after which it begins to wear off and the functions which were disrupted by the anaesthetic gradually return, often displaying aphasic errors (Bear et al., 2007; Wada and Rasmussen, 1960). During the time in which the patient is anaesthetized, he or she is assessed on their ability to use language. If the left hemisphere is anaesthetized and is the dominant hemisphere, the patient loses all ability to speak, whereas if the left hemisphere is anaesthetized but the right hemisphere is dominant, the patient will continue to speak throughout the procedure (Bear et al., 2007).

In a study published in 1977, Brenda Milner used the Wada test to demonstrate that 98% of right-handed people and 70% of left-handed people have a dominant left hemisphere with regards to language and speech function. Her results also showed that 2% of right-handed people have a dominant right hemisphere, which is the same percentage of patients that display aphasia following a lesion to the right hemisphere (Branch et al., 1964).

This procedure is also used prior to brain surgery in order to determine the dominant hemisphere, so as to avoid removal of an area associated with speech and language.

Functional transcranial Doppler ultrasonography

Functional transcranial Doppler ultrasonography (fTCD) is a non-invasive method for examining event-related changes in cerebral blood flow velocity in the middle cerebral arteries(Knecht et al., 1998). This technique can reliably assess which hemisphere is dominant and to what extent, which regards to language lateralization. Studies using fTCD have shown a linear relationship between handedness and language (Knecht et al., 2000).

Electrical stimulation, TMS and Imaging

Electrical stimulation was pioneered by Wilder Penfield and his colleagues at the Montreal Neurological Institute in the 1930s, and helped to identify certain lateralized areas associated with speech and language. Electrical stimulation is the application of an electrical current directly to the cortical tissue of a patient who is conscious. Penfield found that stimulating the left frontal or temporal regions of the left hemisphere with an electrical current accelerated the production of speech. He also found that stimulation can cause inhibition in complex functions like language, as applying a current to the areas associated with speech production in the left hemisphere while the patient is engaged in speech serves to disrupt this behaviour (Penfield, 1963). This procedure is performed during surgery while the skull is removed, and as such it is not a commonly used method of assessment.

Transcranial Magnetic Stimulation (TMS) is a non-invasive procedure, often combined in studies with MRI, which has helped to map the regions associated with speech, showing lateralization to be dominant in the left hemisphere. TMS has also shown that, following brain injury, it is more likely that it is the tissue surrounding the lesion that acts in a compensatory way rather than the opposite hemisphere providing compensation. The major drawback of TMS is, of course, the fact that the magnetic stimulation must pass through the scalp, skull, and meninges before stimulating the brain region of choice.

Imaging studies have proven to be incredibly useful in determining lateralization of language abilities. Functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) have been able to show the complex circuitry associated with speech and language; they have also proven to be consistent with the findings from previous lesion studies, as well as Penfield’s electric stimulation (Bear et al., 2007). There has been some controversy regarding bilateral activation shown in fMRI studies, the reasons unknown, however it has been suggested that perhaps the right hemisphere is involved in aspects of speech that are not measured by such tests as the Wada procedure (Bear et al., 2007). A significant finding is that fMRI results during developmental years show activation during speech and the use of language mainly in the left hemisphere, providing further evidence in support of left hemisphere dominance (Bear et al., 2007).

Cerebral Dominance: Language Functions of The Left and Right Hemispheres

The perisylvian cortex of the left hemisphere is involved in language production and comprehension, which is why it is often referred to as dominant, or said to "speak" (Ojemann, G. A., 1991; Purves et al., 2008). Roger Sperry and his colleagues’ split-brain studies have shown that the left hemisphere is also responsible for lexical and syntactic language (grammatical rules, sentence structure), writing and speech (Purves at al., 2008). Other aspects of language which are thought to be governed in most people by the left hemisphere include audition of language-related sounds, recognition of letters and words, phonetics and semantics.

The right hemisphere, though generally not dominant in terms of linguistic ability, has its role in the use of language. Split-brain studies present evidence that, despite the right hemisphere having no “speech,” it is still able to understand language through the auditory system. It also has a small amount of reading ability and word recognition. Lesion studies of patients who have right hemisphere lesions show a reduction in verbal fluency and deficits in the understanding and use of prosody. Patients who have had their right hemisphere surgically removed (hemispherectomy) show no aphasia, but do show less obvious deficiencies in areas such as verbal selection and understanding of metaphor. It has thus been concluded that the right hemisphere is most often responsible for the prosodic and emotional elements of speech and language (Purves et al., 2008).

Anatomical Asymmetries

The structural differences between the right and left hemisphere may play a role in the lateralization of language. In the nineteenth century, anatomists observed that the left hemisphere’s Sylvian fissure (lateral sulcus) is longer and less steep than that of the right (Bear et al., 2007). In 1980, Graham Ratcliffe and his colleagues used evidence of this asymmetry of the Sylvian fissure, shown in carotid angiogram, combined with results of Wada testing, and found that individuals with speech regions located in the left hemisphere had a mean difference of 27 degrees in the angle of the blood vessels leaving the posterior end of the Sylvian fissure, while those with language located in the right hemisphere had a mean angle of zero degrees.

File:Planum temporale.jpg

Asymmetry of the planum temporale. Image obtained from Labspace:Understanding Dyslexia

In the 1960s, Norman Geschwind and his colleagues at Harvard Medical School found that the planum temporale, the superior portion of the temporal lobe, is larger in the left hemisphere in almost two thirds of humans (Geschwind & Levitsky, 1968), an observation which was later confirmed with MRI (Bear et al., 2007; Purves et al., 2008). This asymmetry exists even in the brain of the human fetus (Bear et al., 2007). The correlation of this asymmetry with the left hemisphere’s language dominance is refuted by many due to the fact that 67% of people show this structural asymmetry, while 97% show left hemispheric dominance. Another problem which exists in examining asymmetry of the planum temporale is how the anterior and posterior borders of this region are defined, and the fact that investigators differ in this definition. This is especially a problem when the transverse gyrus of Heschl, used to mark the anterior of the planum temporale, appear in double (which is not unusual). There are differing opinions as to whether or not the second transverse gyrus should be defined as being within the planum temporale, or outside of it (Beardon, A. A., 1997).

Proposed Correlations

Handedness

The correlation between handedness and hemispheric lateralization is described in the results of the Wada test, described above. The majority of the population is right handed (approximately 90%), and the Wada test results propose that 93% of people’s left hemisphere is dominant for language (Bear et al., 2007). A linear relationship between handedness and langage has been shown using fTCD in a study done by Knecht et al. (2008); their findings show an 27% incidence for right hemisphere dominance in their group of left-handers, a finding consistent with the notion of there being a linear relationship between handedness and incidence of right hemisphere dominance in left-handers (Knecht et al., 2000). This study used a word generation task, and admits that perhaps a measurement of prosody or other such suspected right hemisphere functions may have a different relationship with handedness (Knecht et al., 2000). It is also true that correlation does not necessarily imply causation, and it is also suggested that there is no direct relationship between handedness and language at all, as the majority of left-handers also have their language lateralized in the left hemisphere (Purves et al., 2008). It is, however, a physical example of functional asymmetry, and it is certainly possible that a more substantial connection between handedness and language will be found.

Sex Differences

The tendency for women to score higher than men on language-related tasks is perhaps the result of the fact that women also tend to have a larger corpus callosum than men, indicating more neural connections between the right and left hemispheres. fMRI studies show that women have more bilateral activation than men when performing rhyming tasks, and PET studies show that women have more bilateral activation than men during reading tasks. Perhaps the bilateral activation implies the use of what are thought to be right hemisphere language abilities, such as prosody and intonation. Research has also shown that women have a greater ability to recover from left hemisphere brain damage; the evidence provided by the imaging studies in combination with the results of recovery following injury have led to the controversial suggestion that language is more unilateral in men than in women.

Sign Language and Bilingualism

Sign language has shown to be lateralized in the left hemisphere of the brain, in the left frontal and temporal lobes. This is known through the use of lesion studies, in which the patients had left hemisphere lesions in the areas associated with language which impaired their ability to sign, while right hemisphere lesions in the same areas show no linguistic deficit (Hickock et al., 1998). Lesions in the right hemisphere of signers did, however, show a limited use of spatial information encoded iconically (which is when the sign is similar-looking to its referent). This is in keeping with the belief that visuo-spatial ability is a right hemisphere function and suggests that the role of the right hemisphere in sign language is in the non-linguistic features of sign language.

Bilingualism is thought to be an overlapping of populations of neurons corresponding to each language, all of which are located in the frontal and temporal regions of the left hemisphere associated with speech comprehension and speech production.

Culture and Language Lateralization

When thinking of language there is a tendency to focus on that language in which you think, however it has been proposed that lateralization of language functions can vary from culture to culture. Asian languages show more bilateral activation during speech than European languages, likely because Asian languages employ a far greater use of right hemisphere abilities, for example prosody, and the use of spatial processing for the more “pictorial” Chinese characters; Native American languages also show a good deal of bilateral activity.

Reorganization following brain injury

Studies have been done following brain injury to determine the level of recovery of language and speech ability, and whether or not recovery is based on lateralized function. Bryan Woods and Hans-Leukas Teuber looked at patients with prenatal and early postnatal brain injury located in either the right or left hemisphere and drew several conclusions. First, if the injury occurs very early, language ability may survive even after left hemisphere brain damage. Second, they found that an appropriation of language regions by the right hemisphere is responsible for the survival of these abilities, but because of this there is a tendency for visuo-spatial ability to be diminished. Third, right hemisphere lesions have the same effect in prenatal and early postnatal patients as they do in adults. Brenda Milner and Ted Rasmussen used the Wada test to determine that early brain injury can cause either left, right or bilateral speech dominance, and that those who retained left hemisphere dominance had damage that was not in either the anterior (Broca’s) or posterior (Wernicke’s) speech zone. Those whose dominance shifted to the right hemisphere most often had damage to these areas. Milner and Rasmussen also found that brain damage which occurs after the age of 5 does not cause a shift in lateralization but rather reorganizes within the hemisphere, potentially employing surrounding areas to take responsibility for some aspects of speech.

In patients who have had hemispherectomy of the left hemisphere, the right hemisphere can often gain considerable language ability. When performed in adulthood, speech comprehension is usually retained (though speech production suffers severe deficits); reading capability is small, and there is usually no writing capability at all.

Learning Exercise: 8 Questions on Hemispheric Language Lateralization

1. In terms of hemispheric lateralization and split-brain patients (individuals which have had commissurotomies), if the word “pencil” was presented to the right field of vision of a split-brain patient and he/she was asked to report what they had seen, the patient would respond:

a) by selecting a pencil with the contralateral hand

b) by saying the word “pencil”

c) by saying “nothing is there”

d) by selecting a pencil with the ipsilateral hand

2. The left hemisphere is responsible for all aspects of syntax, except parsing. True or false?

3. What is the structural evidence given to explain the fact that women tend to score higher than men on language-related tasks? What implications might this have on gender differences in patients with aphasia?

4. What 3 conclusions did Bryan Woods and Hans-Leukas Teuber draw regarding the reorganization of language ability following brain injury? Would there be differences in such reorganization in people who are hearing impaired?

5. Through what anatomical system is the right hemisphere able to understand language? What happens to language ability following a removal of the right hemisphere? In what ways do individuals who have had their right hemisphere removed differ from split-brain patients?

6. What were the symptoms of the patient “Tan” which, when presented to neurologist Paul Broca in 1861, propelled Broca to his theory regarding hemispheric language lateralization? Based on current methods of assessment, would Broca's theory still be considered valid today? Why or why not?

7. Which type of study would be best used in order to assess anatomical asymmetry and why?

8. Which type of study is most useful in assessing the connection between hemispheric language lateralization and handedness, and why?

References

Beaton, A. A. (1997). The Relation of Planum Temporale Asymmetry and Morphology of the Corpus Callosum to Handedness, Gender, and Dyslexia: A Review of the Evidence. Brain and Language 60, 255–322

Bear, M. F., Connors, B. W., Paradiso, M. A. (2007). Neuroscience: Exploring the Brain, 3rd edition. Lippincott Williams & Wilkins: USA.

Branch, C., Milner, B., Rasmussen, T. (1964). Intracarotid Sodium Amytal for the Lateralization of Cerebral Speech Dominance. Journal of Neurosurgery, Vol. 21, No. 5, pp 399-405.

Clower, W. T., Finger, S. (2001). Discovering Trepanation: The Contribution of Paul Broca. Neurosurgery, Vol. 49, No. 6, pp 1417-1426.

Geschwind, N., Levitsky, W. (1968). Human Brain: Left-Right Asymmetries in Temporal Speech Region. Science, New Series, Vol. 161, No. 3837, pp. 186-187.

Hickok, G., Bellugi, U., Klima, E. S. (1998). The neural organization of language: evidence from sign language aphasia. Trends in Cognitive Sciences, Vol. 2, No. 4, pp 129-136.

Jay, T. B. (2003). The Psychology of Language. Prentice Hall: New Jersey, USA.

Knecht, S., Deppe, M., Ebner, A., Henningsen, H., Huber, T., Jokeit, H, Ringelstein, E.-B. (1998). Noninvasive Determination of Language Lateralization by Functional Transcranial Doppler Sonography : A Comparison With the Wada Test. Stroke, Vol. 29, pp 82-86.

Knecht, S., Deppe, M., Drager, B., Bobe, L., Lohmann, H., Ringelstein, E.-B., Henningsen, H. (2000). Language lateralization in healthy right-handers. Brain, Vol. 123, pp 74-81.

Kolb, B., Whishaw, I. Q. (2009). Fundamentals of Human Neuropsychology, 6th edition. Worth Publishers: USA.

Ojemann, G. A. (1991). Cortical Organization of Language. The Journal of Neuroscience, Vol. 7, pp 2281-2287.

Penfield, W. (1963). The Brain's Record of Auditory and Visual Experience. Brain, Vol. 86, No. 4, pp. 595-696.

Purves, D., Augustine, G. J., Fitzpatrick, D., Hall, W. C., LaMantia, A., McNamara, J. O., White, L. E. (2008). Neuroscience, 4th edition. Sinauer Associates, Inc.: Massachusetts, USA.

Wada, J., Rasmussen, T. (1960). Intracarotid Injection of Sodium Amytal for the Lateralization of Cerebral Speech Dominance Experimental and Clinical Observations. Journal of Neurosurgery, Vol. 17, No. 2.

For many years I have worked on the documentation and development of endangered languages, mainly in West Africa, and there are three factors which have always struck my attention, prior to issues of revitalisation.

The first is that the decision to retain a language must come from the community on the basis of community self-esteem, and not be decreed by linguistic imposition, however well-meaning. Many languages have come and gone in the past 200000 years.

The second is economics: if there is economic motivation to retain a language, then the community will, likely as not, decide on this.

The third, and most important, is the younger generations: if the young people are motivated to develop their own culture in the language, then they are likely to do this. It is not only the older generation which often fails to practise intergenerational transmission, but also the younger generation under peer pressure from the broader context which rejects this.

The how and what of revitalisation comes in after this, and is very culture-specific.

Thank you, Dafydd. I agree with what you have written.

In 1978 I married a young woman from an Otomí-speaking community in the central highlands of Mexico, and I learned to appreciate the language and the people that spoke it. Over the decades, in academic settings, I have worked to recover Otomí history and get in into the hands of colleagues, Mexican society in general, and of course the Otomí people themselves. Like-minded colleagues have formed networks and we have made some progress, including 17 annual congresses, several proceedings volumes, a journal, and programs designed to reach a broader public. Since the sixteenth century there has been a very negative stereotype of these people in published texts, so I think this course of action helps build what you call "community self-esteem", which of course is fundamental in language revitalization.

Your second point was one thing several of the participants in the World Conference on Linguistic Rights in Barcelona agreed upon, citing specific policies and projects. Mexico passed a very advanced linguistic rights law in 2003, giving all 364 native speech varieties the status of official languages with specific rights. Of course applying this Utopia to daily life is an enormous challenge and requires a great deal of effort and support. One example is that native speakers have the right to receive attention from government authorities in their mother tongue. This, if it were to be implemented on a widespread scale, would create relatively high-prestige jobs in municipal governments, translating laws and official documents, and attending people in their languages. Thus speaking and writing one's language well would be seen as a key to obtaining a job in the "big house" (dängu in Otomí) where local and regional power is wielded. Other actions include the professional (i. e. paid) use of native languages in mass media and on the web.

The first two factors, along with reforms and effective bilingual programs in primary and secondary education, would seem to be prerequisites for the third; young people would have more pride in their cultural and linguistic heritage, and would see that there can be economic benefits to having proficiency in the use of their mother tongues.

There is a good reason why I emphasize the third point, acceptance by the young people: young people are often not so interested in what the older generation consider to be their cultural heritage, particularly in the modern age. Schooling is important, but the youngsters have the language already and need to develop their own subcultures, like young people everywhere. All too often they are alienated by prescriptions of correctness by their less imaginative seniors who disapprove of changing language as 'slang', for example. Yet after all it is the young people who carry the responsibility for the future of a language and culture, therefore their interests must be respected.

Dafydd: I think you are correct on this. In Mexico there are languages with a strong base among the upcoming generation and others which are being rapidly abandoned by the young; the latter tendency seems to be prevailing, but I haven't looked hard at the latest demographic figures.

I am hoping ResearchGate users will have some case studies to share. I have heard of success stories in other parts of the world, among the Maori and the Sami peoples, for example.

The PBS flim, We Still Live Here, about the revitalization of the Wampanoag (Native North American Algonquian) language is an excellent and unique case study. Here is the link to the PBS webpage for it: http://www.pbs.org/independentlens/we-still-live-here/film.html. In addition to the excellent points made by Dafydd Gibbon and David Wright-Carr above, this film shows how the process of revitalization itself can be embedded within the framework of evolving cultural and spiritual beliefs. Spiritual events in the process of revitalization mutually reinforce both cultural beliefs and the value of language revitalization. The film also shows a highly creative collaboration between members of the Wampanoag nation and linguists working on language recovery from historic documents and in community programs. Well worth it to view this video! One shortcoming, however, is that the film does not continue into a phase of revitalization in which the Wampanoag language comes into everyday use among a significant portion of the population.

Thanks, Cory. This case study highlights the importance of documenting languages that may be on the verge of extinction. Descriptive studies are necessary tools for adults who have not learned their ancestor's tongues at home but wish to acquire some proficiency for whatever reasons. Scholars have an important role to play in this process, as can be seen here.

I have been in the shoes of the "white man" who offers the results of his studies to groups of native speakers, as in the video, but happily the initial protest has always given way to friendly collaboration. What is important here, I think, is maintaining a horizontal gaze, rather than a "missionary" attitude which looks down from a false sense of cultural superiority.

Of course, other elements of culture go hand-in-hand with language, and revitalization depends on strengthening entire symbolic networks of which language is just a part. These networks may include music, dance, ritual performance, visual arts, culinary arts, and much more.

As Dafydd points out, each generation decides what elements to incorporate into their emerging identities and which to discard. Preventing or minimizing external and internal processes of discrimination can give young people more options in this process.

Hebrew of course is the classic success story. They had a long written tradition and lots of state support, something most endangered languages can't count on.

Check the links for other ideas: http://jan.ucc.nau.edu/~jar/RIL_1.html

The Crawford article ("Seven Hypotheses...") is one I've found especially useful: http://jan.ucc.nau.edu/jar/SIL.pdf

Dafydd, of the three factors mentioned by you I think the one that bothers me the most is the second factor. In a country like India economic motivation can be linked only with English. I cannot think of any way speakers of endangered languages can be motivated economically. Though the first factor that you mentioned is relevant to many communities, in the case of the language that my research focuses on, though there is a strong interest in culture maintenance it is not apparent in the language itself due to the dialectal variations in different states where the speakers are geographically scattered.

Meenakshi Sirigiri, you are quite right. None of the 'recipes' is universally valid, as each situation is different. India has an ancient multilingual culture, and I wonder if it is not an exaggeration to link economic motivation in India only to English? I have spent small amounts of time in India, working with linguists and also speech technologists, and have the impression that at least other major languages such as Hindi, Malayalam, Gujarati and several others are also powerful factors. Naturally they are not endangered languages. The Tibeto-Burman languages of the North-East are more disadvantaged, as are other minority languages, but I believe that economic development programmes would help to strengthen local self-esteem. That these are needed seems clear from the revolts by young people in various parts of India.

That's interesting material, Aurolyn, thanks.

Yes, the article by James Crawford has useful insights.

In the Native American context, indigenous languages best serve local communities. Revitalized cultural systems have developed in English. The major one - powwow - is also an ethnic economic enclave. English serves its intertribal membership. Therefore, it is necessary to find other social contexts in which young people of any given Native nation might spontaneously wish to speak their indigenous language among themselves. Little short of childhood emersion would seem to serve this purpose. School and home are the sites for this language in action. Hence, my Anishnaabe colleague, Alan Corbiere, who designs Anishnaabe language programs for K-12 Anishnaabe First Nations schools, laments that it is a monumental challenge to get beyond conversations like, "What do want for breakfast."

We - core members of GRASAC (Great Lakes Alliance for the Study of Aboriginal Culture) - are working on integrating Native American languages into a multimedia database of cultural heritage items from the Great Lakes region. This is new methodology that we are developing, and consequently the process is very slow. In whatever context and through whatever means, however, I believe that achieving Dafydd's point about youth buy-in is critical to fluency and retention. In this respect, close attention should be paid to the local social settings in which youth might employ the language - only some of which might concern economic incentives. I don't know any examples of such strategies, and I would be very interested to learn of any.

Cory, one case in point is the revitalisation of Welsh over the past few decades. These are my own informal observatins (I have not investigated whether there are studies). A major influence, as I see it, is what I call the 'cool factor' for young people. In addition to official language support (school, media, bilingual forms, roadsigns, etc.) there is support for youth activities, including both competitive and cooperative scenarios, in music, games, art. There was also some resistance by more conservative older speakers to innovations by young people. Also an odd situation developed in some cases: kids could communicate in Welsh with their grandparents but not their parents, and they had a 'secret language'. Whether these observations can be borne out by a proper study, or generalisable, I can't say.

in the case of Zenete in the south of Algeria, revitalization consists of daily radio broadcasts and folk poetry, the Ahellils. But, there is no other governmental support to promote the language variety and help revitalize it.

More than governmental support, native speakers who care about the maintenance of their language are vital. If these last tend towards another variety for individual and/or social reasons, and do not give any value to their ancestral mother-tongue, the latter is doomed.

Dafydd - the Welsh example is interesting indeed - Thanks! I've seen the street signs in documentaries. I think politics has something to do with the meaning of "local" speaking communities. Although Wales certainly has had its colonial struggles, at least there is a geographically bounded territory where language revitalization can be centered. As fourth world nations, Native American indigenous language speaking communities are geographically dispersed over wide territories with only small pockets of potential speakers in any one place. Sorry for the lack of fine tuned comparison - I'm sure there are similarities of which I am less aware. I would like to learn more about the Welsh example - wish it were published.

I thought about realms such as "music, games and art," but unfortunately in the Native American context these are mainly intertribal activities that require English as a common language. GRASAC hopes to implement some workshops for making arts and crafts that are more specifically Anishnaabe rather than pan-Indian. As the powwow culture is evolving to emphasize tribal identities more than mere Indianness, there is hope that the social venue of making arts could become a site for indigenous languages. Young people mainly enter these speaking communities through the desire to make their own powwow regalia, however, so we are also trying to think of ways to create bridges from powwow material culture to largely unknown historic genres of arts. So far, community members of all ages have shown little interest in reviving these historic arts, so it is an unresolved challenge. This brings us back full circle to the holistic embeddedness of language in action.

In Chile we have the case of mapudungun, great efforts have been made to revitalise this precolombian language, though since no more than 20 years, before that the public policies on education were the use of only spanish in schools, a monolingual country and monocultural for the sake of the republic formation. Since the nineties this seemed to have changed but aboriginal languages lost about four hundred years of development.

Dafydd, thank you for that response. However, what I meant by economic motivation was more specifically employability. The state or regional languages like Gujarati, Malayalam or Telugu are not endangered as of now, but it is hard not to visualize a time in the future where they might be. In so many urban economically well to do families English has almost replaced the home language- there is no intergenerational transmission and children are taught and encouraged to speak English right from when they begin speaking. ( a belief in the critical age theory...)

As regards minority languages with no script they are definitely endangered. Besides there are so many political and policy matters. The 'Tulu' language with about 17 lakh speakers features on the endangered languages list but the language that my research focuses on 'Patkar' with about 4 lakh speakers does not.

If you could possibly give me an example of an economic development programme that you have mentioned, I would be able to understand better.

In the Native North American context, I am aware of one language which was extinct and has been reconstructed: it is Huron-Wendat speaking which was lost for the profit of French. Recently some excellent work has been done to reconstruct the language with the help of Wyandot which is a dialect closely related to wendat and stil spoken.

In the case of very fragile languages, I would suggest one obvious strategy is to make some advances in the writing methods of that language that may help to revive it and to eventually make translations possible of major works in other language.

There is a thesis on this subject (in French): www.archipel.uqam.ca/4302/1/D2242.pdf‎

There is also the work of Lynn Drapeau of UQAM which published a book which contain an article describing the story of huron-wendat language revitalization. The article I read was in this volume: Drapeau, Lynn. 2011. Portrait d'un patrimoine en danger. Lynn Drapeau (réd.). Les langues autochtones au Québec : Un patrimoine en danger. Québec : Presses de l'Université du Québec. pp. 7-17. http://www.priceminister.com/offer/buy/149432531/les-langues-autochtones-du-quebec-un-patrimoine-en-danger-de-lynn-drapeau.html

Hope these informations are helpful.

Thanks Eric! The Wendat example is helpful and these are useful sources. We eventually hope to include Wendat in the GRASAC database project. The strategies are very similar to the Wampanoag case in which they also used written Wampanoag and closely related Algonquian dialogues to reconstruct lost terminology. The effort to standardize Anishnaabe spelling has been ongoing among native speakers and instructors since the 1980s, and I think it has helped. Unfortunately, I don't read French well enough to fully comprehend the work on Wendat, but I appreciate your multilingual contribution!

Eric, your suggestion of translating classical works in other languages is interesting. An Otomí colleague and friend from the state of Hidalgo in central Mexico, Raymundo Isidro Alavez, has adopted just such a strategy for revitalizing his mother tongue. He started by translating *Visión de los vencidos*, a compilation of native accounts of the Spanish Conquest by Miguel León-Portillo, into Otomí. He continued with Antoine de Saint-Exupéry's *Le petit prince*. He pulled together institutional support and both were published in handsome editions. His latest published translation, hot off the press, is Juan Rulfo's *El llano en llamas*, a masterpiece of Mexican literature from the mid-twentieth century, which now can be read in Otomí. Previous literature available in Otomí usually dealt with native culture and traditions, which I also think is great. Raymundo is now hard at work translating Cervantes' masterpiece, Don Quijote. (Pioneers in this area, of course, were the Wycliffe Bible Translators, with their scientific front operation, the Summer Institute of Linguistics. They have made profound contributions to linguistics and literacy in native languages, albeit without the "horizontal gaze" of respect for native culture that I prefer, as mentioned above.)

in the Gourara, in the area of Timimoun, Zenete is kept alive through folk songs known as the Ahellils. They are written in arabic letters but the lyrics are either a mixture of Arabic and Zenete or zenete only. As such the local community protects its ancestral language from loss.

Thanks Cory and David for your comments. I now remember also the work of Eugene Nida and his followers/school who were the first to work at a large scale in translating the Bible in many languages and especially in Native ones. I don't know for sure if they were convinced that their work was contributing to revitalizing these languages, but I think it surely helped somehow.

Thinking about it, translation might also be a good measure of the power of a language: the more translations are made available from a language, the more that language might be considered powerful or attractive compared to others. I don't know the numbers but they should be interesting to study.

Éric

Another dimension of support for local languages (including endangered languages) is the involvement of speech and language technologies, not only for recording, annotation and documentation, but also for further development.

For example, you may be interested in checking out the LLSTI (Local Languages Speech Technology Initiative) project, in which I was involved, described in these documents:

http://www.flarenet.eu/sites/default/files/lrec2008_cocosda-write_workshop_trippel.pdf

http://share4dev.info/telecentreskb/documents/4051.pdf

Sometimes legacy documents can be 'revitalised' by computational processing, as with the Ibibio dictionary, which was scanned from an older dictionary by Elain Kaufman, processed with Optical Character Recognition (OCR), converted to a database, extended with modern entries, and made available as a pdf document:

http://coral.lili.uni-bielefeld.de/Courses/Summer04/Lexicography/IbibioDictionary/ibibio_dictionary01.pdf

Further possibilities are web tools for language analysis, such as the corpus analysis site which I developed for Uyghur (not an endangered language, of course):

http://wwwhomes.uni-bielefeld.de/gibbon/ULex/

There are many other web-based tools, of course, which are too numerous to be listed here.

Further hints:

1. Check the work going on at the School of Oriental and African Studies, London.

2. Note this forthcoming book: http://www.cambridge.org/us/academic/subjects/languages-linguistics/sociolinguistics/keeping-languages-alive-documentation-pedagogy-and-revitalization

I am surprised that neither Hebrew in Israel--a reconstructed language--nor that of Irish or Gaelic have not been discusses. I encourage experts on those language's developments to comment.

I currently live in Oman, namely in the Dhofar region, where local languages are not promoted at all--although here there are a large number of speakers of Gabali and Mahari languages & dialects. As far as I know, not even a writing script exists for these two languages.

I am aware that the University of Hawaii at Kona offers a doctorate to those who speak and wish to study language preservation and promotion base upon the Island chains were on indigenous languages. The leaders of that program believe they have an exportable model based on their training and development experiences.

I have a paper that outlines some strategies I used to document and help revitalize aspects of the Zhuang language of southwestern China. Here is a link to the abstact of the paper: http://www.tandfonline.com/doi/abs/10.1080/15595690903442298?journalCode=hdim20

Sadly, I couldn't locate the journal in the data base for the library here in Brazil.

Let me see if I can upload a file of the paper...I think it works, let me know if you receive the file, and can read it.

Thanks, it worked!

Yes it worked; thnx a lot dr. Bodomo. I am really interested in saving an endangered language in southern algeria called taznatit and i really did not have any idea about how to do that for real. Thnx again.

so far, I got the attention of the Haut Commissariat à l'Amazighité (HCA) as to the endangered nature of Taznatit. And last December, the HCA organised an Int'l conference entitled "Sahara, creuset des civilizations Amazighes". My communication was titled 'Zenete, an endangered language variety in southern Algeria'.

Apart that, I always encourage my students to write final projects 'memoirs' about their own mother-tongues, whether Arabic or Zenete and Tamachek

My book "Die Mundart der Hyayna in Marokko (514 pages" deals about this topic, but it is written in German and I hope I can translate it one day into english and french.

Mr Bachir, I appreciate your way of encouraging yours student to write final projects about their own mother-tingues, because it´s the best way to show them, that their languages are worthfull and must be protected through their analysis. I did the same think too with the students with Tamazight as a mother-tongue and I ´m trying now to settle Tamazight at the translation university where i studied in Germany, because we need absolutely sworn translator from and into Tamazight.

thnx a lot Rachida. I wish i could do more than that to revitalize Zenete.

Peter Austin has written a paper that I saw on academia.edu that also touches on the subject. Language documentation twenty years on To appear in Martin Pütz and Luna Filipovic (eds.) Endangered Languages across the planet: Issues of ecology, policy and documentation. Amsterdam: John Benjamins. 

I have been working on two endangered languages, one in the Amazon, one in Papua New Guinea. If another language is valued more than the mother tongue, i.e., a lingua franca, revitalization is really very difficult, maybe impossible.

But enthusiasm jumping over to members of a community speaking an endangered language is the start.

Thank you Carola. I agree about the motivation factor. Lately my colleagues and I have been working on using Otomi, an indigenous language from central Mexico with less than 300,000 speakers, in publications, art exhibitions, and radio programs. These are small contributions; I hope they help in some way. There has been a renewed enthusiasm and pride in using the nine variants of Otomi, but this may have come a bit too late, as most young people with Otomi-speaking parents are not using their mother tongue.

Here are the cover and flaps of a trilingual edition of a children's version of Don Quixote, in Otomi, Spanish, and English, a project I had the privilege of participating over the last two years. The artist who created the illustrations, José Luis Romo Martín, is a native speaker of Otomi and worked on leaves of Agave cacti, a bountiful and sacred plant for this ethnic group. The translator, Raymundo Isidro Alavez, has an unusual strategy for revitalizing his mother tongue: translating masterpieces of universal literature into Otomi.

https://www.researchgate.net/publication/274375585_Ndada_Hongahogam%27ui_pa_ya_btsi_Don_Quijote_para_los_nios_Don_Quixote_for_children

Book Ndada Hongahogam'ui pa ya bätsi / Don Quijote para los niños...

We have continued with the Quixotic project of translating classic works of literature into Otomi, with the support of the Museo Iconográfico del Quijote in Guanajuato. A trilingual (Otomi-Castilian-English) children's edition based on the Maya K'iche' classic, the Popol Wuh, is now available. Attached are files with images of the front and back covers and flaps.

https://www.researchgate.net/publication/315613316_Popol_Wuj_pa_ya_batsi_Popol_Wuj_para_ninos_Popol_Wuh_for_children

https://www.researchgate.net/publication/315613461_Popol_Wuh_back_cover

https://www.researchgate.net/publication/315613463_Popol_Wuh_front_flap

https://www.researchgate.net/publication/315613464_Popol_Wuh_rear_flap

A trilingual edition of Le Petit Prince, by Antoine de Saint-Exupéry, is forthcoming.

Book Popol Wuj pa ya bätsi / Popol Wuj para niños / Popol Wuh for children

Data Popol Wuh: back cover

Data Popol Wuh: front flap

Data Popol Wuh: rear flap

David,

''

Language nests, which are immersion-based early childhood language education programs, have been successful in many communities in danger of losing their language. The idea originated during Maori revitalization efforts in New Zealand, and has been implemented in Hawaii and across Australia.

In Canada, these programs exist in several provinces and territories, including British Columbia and the Northwest Territories. The latter has over 20 nests, covering all the official Aboriginal languages of the territory.''

http://www.mcgilldaily.com/2014/03/revitalizing-endangered-languages/

''Only three of the 50-70 languages in Canada (Cree, Inuktitut and Ojibway) are expected to

remain and flourish in Aboriginal communities ''

http://www.fpcc.ca/files/pdf/language-nest-programs_in_bc.pdf

Thanks for the positive news, Louis. Canada's project is encouraging. The Maori case is recognized among language rights activists as having been exceptionally successful. It was prominently featured at a meeting I attended in Mexico City, the First International Forum on Successful Experiences of Teaching Indigenous and Minority Languages, sponsored by Mexico's National Institute of Indigenous Languages (2007). I'm attaching a few photos to give a glimpse of how people from several continents have been working together and sharing their experiences to revitalize minority languages throughout the world.

The experience of the American missionaries in Urmia  in persia could be used when they succeeded in reviving the ancient Syriac language. They succeeded in issuing special dictionaries until they became known as modern Syriac. This was during the nineteenth century

Dear Asim:

The Summer Institute of Linguistics, a group of Protestant Christian Missionaries that originated in the United States of America, has done a lot of extraordinary work toward linguistic documentation, analysis, description, and revitalization throughout the world. The results are on their web page (https://www.sil.org/). Without their work we would have a much poorer collective knowledge about the world's languages, and many languages would be less vital or even extinct. I have used their linguistic publications extensively in my research.

The only thing that bothers me about this is that their goal is to translate the Bible into all languages, as part of a general program of missionary proselytism. This goal has not always been clearly stated.

In my opinion, when engaging in intercultural communication and cooperation, it is healthier to assume a horizontal gaze, accepting the cultural traditions of other people --including their religions--, rather than assuming that one's own traditions are somehow superior to those of others. In general terms, I believe that there is an element of respect missing from the missionary point of view.

Best regards,

David

David,

The language revival function of these missionaries may be seen as an exaptation of these activities.  Some of the ancient religious practices of many people have survived into christian forms and may actually have not survive to the modern world if not transmutted that way.  The christian easter celebrations have been located in the Spring in order to transmitted the ancient spring festivities of the ancient religions.  The easter eggs have nothing to do with Jesus but here the ancient traditions uses christianity to continue.  So who transmute who? 

All human contacts/interaction between people of profoundly different culture will necessarily create a cultural effect.  Make me think to the measurement problem in the physics of elementary particle.  Even the interaction done with the best intend, the highest respect, will be done from a given viewpoint and may have bad effects. The modern scientific mindset may have more toxic effect for these culture than the missionaries had.  Bot had the best intentions from their perspectives but both perspective is foreigh.  There is an intrinsic cultural interaction problems in human affairs.

 Extinction of cultures/languages is a result of the worse kind.  Each time an culture/language get extinct, it is one unique side/aspect of our humanity that dye.  Survival of the humanities is more than a survival of our physical bodies. UN mobilize for famines, not enough.  Effort are done (not enough) for saving living species from extinction; our modern industrial lifestyle being responsible for the current great extinction of life on earth.  But our modern industrial lifestyle (modernity) is also responsible for the current cultural genocide (great extinction) of humanity.  We still do not realize that we are part of bigger cultural body that the little one we got enculturated in.  Industrial farming concentrate the bulk of the food production with less and less varieties of plants and animals.  Human had created a use genetic pools of plants and animals for their food productions over the age and now this capital is being depleted and some are trying to create genetic bank in  order to save some of it.  These effort at creating language nests are not necessary long term solution but at least constitutes the equivalent of these genetic bank.  When the industrialisation began to decimate the ancient traditional custom in Europe, people like the Grim brothers started to collect the old folk stories of these disappearingg oral tradition and put them in writing and because of that some of these stories are known to us with the social values they promoted.  When in the american west, the practice of cattle by cowboy in the vast prairies dissapeared by the fencing of the prairies, the cow boy culture partially survived by the creation of circus and annual festival such as the Calgary stanpeed.  A lot of ancient human cultures will have to use similar devices in order to partially survive when the modern lifestyle destroy their relation to the land.

Yes, Louis, intercultural contact is a complex matter, with serious ethical implications. I still think that we do a better job of cooperating with one another when we assume the 'horizontal gaze' of mutual respect, to the best of our ability. In the realm of religious beliefs, assuming that one's belief system is the only 'truth,' and that all other systems are wrong, can have negative, even dangerous effects on human relations. This can also occur from a pseudoscientifically academic perspective, when researchers forget that the essential ingredient of contemporary science is to doubt everything, holding all knowledge to be provisional. Humility is a useful ingredient in academic work.

The world is mutating at an ever-increasing rate. We are all in the challenging position of deciding what elements of our cultural heritage continue to be useful, what elements may be modified or discarded, and how we are to adapt to our emerging geographic, biological, and sociocultural contexts.

It is a most interesting resource, Harshad. Thank you for posting the link.

The local languages has roots in history of that region, and therefore embedded in the culture of that. Globalization is true for development of S&T, but it annihilates local cultures and languages.

New era of S&T, is not responsible for smashing local cultures, beliefs and languages; but it is also accountable for gene loss (biodiversity loss) if extended to biological issues.

Globalization is beneficial, but it also seeks prices.

Prof. Gibbon is right. The target should be the youth. We must find ways of building their interest in reviving endangered languages. It should not be directed to only schools, but in communal meetings with societal members, the need for the use of the endangered languages must be highlighted. Usually, when the need for such renaissance of language is tied with the culture of the people and their place identities, many of the young ones who are swam into the numerous contributions of their forebears that ensured the fame of their societies, would be willing to speak it. Innovative ways of introducing language contests and awards would be interesting to revive the passion to utilize the endangered language. How about the elderly ones who hold such endangered languages? Engage the qualified ones as resource persons in schools. We must equally encourage them to speak it in their various households.

Dickson

Very interesting and enlightening discussion by all contributors. Commonality of understanding informs them all - a necessary component of any attempt to revalorise and revitalise languages and cultures about to be jettisoned in favour of others. Ideological extremism can be very harmful. to revitalisation. A combination of distanced scientific methods with ethically responsible care is key to creating positive experiences of these processes for all involved.

Thank you for your answer, Liam. I'm sorry, I don't understand the sentence "Ideological extremism and a combination of distanced scientific methods with ethically responsible care is key to creating positive experiences of these processes for all involved."

The Museo Iconográfico del Quijote, in Guanajuato, Mexico, recently published a trilingual (Otomi/Castilian/English) edition of Antoine de Saint-Exupéry's classic novella Le Petit Prince,* following up on the trilingual editions of children's versions of Don Quixote and the Popol Wuh, mentioned earlier on this thread. Translating classics of world literature into Otomi is one of many strategies to revitalize this native language of central Mexico, spoken today in several regions of Mexico and the United States of America. The illustrations, based on Saint-Exupéry's drawings, are by artist and graphic designer Luciano Trigos; he introduced subtle patterns based on traditional Otomi textiles on the clothing of some of the characters to visually reinforce the "Otomization" of this literary masterpiece. (This may be seen at the top of the attached image, but it is necessary to click on it to see the whole picture.)

The idea is to put these books into the hands of Otomi children living in Mexico and the United States. They are well suited for use as didactic material in bilingual education.

* Antoine de Saint-Exupéry, Ra Zi Ts'unt'u Dängandä / El Principito / The Little Prince, Ángela Piedad and Luciano Trigos, editors, selection and adaptation by Bernardo Govea and Daniel Silva, Otomi translation by Raymundo Isidro Alavez, Castilian translation by Lilia Madrigal and Carlos Mata, English translation by Layla Wright-Contreras, Guanajuato, Museo Iconográfico del Quijote, 2017. (N.b.The vowels of the word Ts'unt'u are underlined, representing a phoneme that sounds like the French /u/.)

I think one of the best ways to revitalise any endangered languages is to involve the identity of the native speakers. Make them proud of their 'language' and culture so that they go back to their ancestral mother tongue at least through the oral means of expression.

Hi David, It's no wonder you couldn't understand it! I've revised it and I think it makes sense now. The page in Otomi is fascinating! Well done.

Got it. Thanks, Liam.

Agreeing with many contributors in this thread that the future vibrancy of an endangered language depends in large part on uptake by the youths of a community today, I'd like to tie some of Meenakshi's important observations to the "Little Prince" excerpt above. One very exciting potential solution to the lack of economic opportunities for young people in many areas where endangered languages are spoken is to get young people involved in the creative work of translation of materials of interest to young people into their own languages. In Arunachal Pradesh (NE India), we have found that the uptake is extraordinary. For example, Galo community members dubbed "Finding Nemo" and "Ice Age 2" into Galo (Nimo No Yoolo? and Tapam Mooko), and these films were distributed and viewed very widely, both in the Galo community and among other language groups. It is likely that no more than a few hundred copies were actually sold, but this was enough to make it worthwhile, at least.

But this is not without challenges. Unfortunately, I was informed that the long arm of Disney's copyright infringement lawyers somehow got word of the Galo-dubbing project and put a stop to it through their usual legal threats. This is at best an irony, since it is completely impossible to purchase a "legitimate" copy of any Disney DVDs in Arunachal Pradesh, never mind one dubbed into Galo or any other local language (others may prefer to assign other descriptions to such behaviour).

But the point here is that the initiatives taken by Galo community members in producing materials which were of interest to young people had both revitalisation and, at least potentially, economic benefits. I am hoping that we might be able to help them organise a means of doing this legally at some point.

We believe that with the need for young people to contribute to the protection of their native language from extinction, this depends not only on this point, but on all the components of society, especially the previous generation of youth, through the establishment of schools or private newspapers in the original language to support their continuity and survival.

The most fundamental strategy for the preservation the native language is the speaking and teaching as well as teaching the present youngest generation with native language.

I have lectured across Europe and found myself getting worried about the extent to which English has started taking over as the language of education in HE contexts - particularly in countries with small populations such as Finland. After one such trip, I had an external examining job in Wales and sat on an exam board where every programme of study had to be made available to the students in Welsh, even if only one student opted to take it. Please double check all of my musings above before quoting me, but the government-supported revival of the Welsh language is a very interesting case.

How could we translate texts into a language variety which is not yet codified, doesn't have a standardised grammar nor a definite script such as is the case for Zenet in southern Algeria?

Education at all levels is important; teachers may need to codify rules of pronunciation, syntax and vocabulary. Links to national/ethnic culture including music are vital. Overall society needs to respect identity of minority groups.

I'm am a Polish-English interpreter. All of you are right. Important is also, that as translator works with thresarus, interpreter often use her/his own words. When I do symultatious interpreting I haven't time to think about extant translation only correct meaning. Most important is to listen carefully from the beginning to the end of the sentence and ask again if any doubt. When I see English movie and I read polish subtitles I'm in shock sometimes though.

Dear Bachir:

If you can get a group of expert speakers of Zenet interested in documenting their language, with the collaboration of specialists in descriptive linguistics and related fields (ethnography, linguistic rights, etc.), such a project would contribute to the revitalization and revalorization of Zenet, and the materials produced would become tools for future projects like literary creation and translation.

If native speakers are paid to do this work, it would be better still. When members of a minoritized language community see that the knowledge and use of their language can make a positive impact on their personal, family, or group financial situation, that language generally gains prestige within its community. Grants are available for such projects, offered by international organizations and by some national governments.

Best regards,

David

@ David Charles Wright-Carr thank you for the suggestion which is worth considering. I already encouraged native Zenete speakers to write memoirs about their mother-tongue; that is a small step but better than nothing.

Focus on these languages ​​by working in specific institutions such as heritage institutions and archaeologists@

@ Bachir Bouhania , at the same time why shouldnt you use phonetic transcription to register the language.. and can you share us what are the problems facing in using traditional method which is 'to collect kennel sentences and vocabulary in transcription and writing grammar of the language'

In India, in Mother Survey project, they collect the linguistic oral data and transform into IPA Phonetic transcription and then they write grammar.

I hope it works

I would look at Ecuador's integration of the language into their general Ministry of Saberes Ancestrales and the concept of Buen Vivir. In Ecuador, native languages in general are well-protected. Another interesting slant would be the whistling language of La Gomera, The Canary Islands, Spain, World Heritage (Intangible) that is on the school syllabus. Hope this helps.

In a nutshell, I would say that Google and the advancement of artificial intelligence has been the most recent impactful contribution for revitalizing endangered languages successfully. Due to the volume of results one can access at their fingertips with Google Search combined with the collective data-mining leaps of artificial intelligence, the sheer vastness of readily available information on the internet alone has been extremely successful to not only educate humankind of other languages, but to simply define what an endangered language even is! The conceptual abstractness of data on the world wide web in our century and even decade is majorly overlooked on it's impact on socio-psychological and cultural awareness.

The Hebrew language is belong into Semit language part and, therefore it 7 million people use it. It is official language of Israel. Language of Israel is used in Palestine area until 3th previous century and therefore it has became writing language however, this language has became speaking language from 19th century for history. Elizer Ben-Ehuda's performance influenced to do above. The Hebrew that is very difficult to restore this language. Because it has been non-used for two thousand years. Many people thought that it is impossible to use again. Above language has only 6000 words and it is in Bible. So, it needed to create too many new words for Hebrew language.

Psycholinguistics/Hemispheric Lateralization of Language

ontents

• 1 Introduction
• 2 The History of Discoveries
  • 2.1 Jean Baptiste Bouillaud and Simon Alexandre Ernest Aubertin
  • 2.2 Paul Broca
  • 2.3 Carl Wernicke
• 3 Methods of Assessing Lateralization
  • 3.1 Lesion Studies
  • 3.2 Split Brain Studies
  • 3.3 Wada test
  • 3.4 Functional transcranial Doppler ultrasonography
  • 3.5 Electrical stimulation, TMS and Imaging
• 4 Cerebral Dominance: Language Functions of The Left and Right Hemispheres
• 5 Anatomical Asymmetries
• 6 Proposed Correlations
  • 6.1 Handedness
  • 6.2 Sex Differences
  • 6.3 Sign Language and Bilingualism
  • 6.4 Culture and Language Lateralization
• 7 Reorganization following brain injury
• 8 Learning Exercise: 8 Questions on Hemispheric Language Lateralization
• 9 References

Introduction

Hemispheric lateralization refers to the distinction between functions of the right and left hemispheres of the brain. If one hemisphere is more heavily involved in a specific function, it is often referred to as being dominant (Bear et al., 2007). Lateralization is of interest with regards to language, as it is believed that language is a heavily lateralized function: certain aspects of language are found to be localized in the left hemisphere, while others are found in the right, with the left hemisphere most often dominant. This was initially proposed by early lesion-deficit models and studies with split-brain patients, and has been shown in more recent years through tests like the Wada test and imaging studies. There have been studies which show that there are anatomic asymmetries located near and around the regions associated with language, and each hemisphere has shown to play its own but separate role in the production and comprehension of speech. The hemispheric lateralization of language functions has been suggested to be associated with both handedness, sex, bilingualism, sign-language, and a variance amongst cultures. It has also been proposed that a reorganization occurs following brain injury that involves a shifting of lateralized function, as long as the injury occurs early in life.

The History of Discoveries

Jean Baptiste Bouillaud and Simon Alexandre Ernest Aubertin

French physician Jean Baptiste Bouillaud (1796-1881) was one of the earliest proponents of hemispheric language lateralization. On February 21, 1825, Bouillaud presented a paper to the Royal Academy of Medicine in France which suggested that, because so many human tasks are performed using the right hand (such as writing), the left hemisphere might be the in control of that hand. This observation implies that language, at the core of writing, would be localized in the left hemisphere. It was already known at this time that motor function was primarily controlled by the hemisphere ipsilateral to the side of the body through lesion studies. Bouillaud also proposed that speech is localized in the frontal lobes, a theory that was carried on by Bouillaud’s son-in-law Simon Alexandre Ernest Aubertin (1825-1893), who went on to work with famed French neurologist Paul Broca in 1861. Together, Aubertin and Broca examined a patient with a left frontal lobe lesion who had lost nearly all ability to speak; this case and several others similar to it became the basis behind the earliest theories of language lateralization.

📷

Paul Broca, image obtained from Clower, W. T., Finger, S. (2001)

Paul Broca

French neurologist Paul Broca (1824-1880) is often credited as being the first to expound upon this theory of language lateralization. In 1861, a 51-year-old patient named Leborgne came to Broca; Leborgne was almost completely unable to speak and suffered from cellulitis of the right leg. Leborgne was able to comprehend language but was mostly unable to produce it. He responded to almost everything with the word “tan” and thus came to be known as Tan. Broca theorized that Tan must have a lesion of the left frontal lobe, and this theory was confirmed in autopsy when Tan died later that year (Bear et al., 2007). In 1863, Broca published a paper in which he described eight cases of patients with damage to the left frontal lobe, all of whom had lost their ability to produce language, and included evidence of right frontal lesions having little effect on articulate speech (Bear et al., 2007). These findings led Broca to propose, in 1864, that the expression of language is controlled by a specific hemisphere, most often the left (Bear et al., 2007). “On parle avec l’hemisphere gauche,” Broca concluded (Purves et al., 2008)- we speak with the left hemisphere.

Carl Wernicke

German anatomist Carl Wernicke (1848-1904) is also known as an early supporter of the theory of language lateralization. In 1874, Wernicke found an area in the temporal lobe of the left hemisphere, distinct from that which Broca had described, which disrupted language capabilities (Bear et al., 2007). He then went on to provide the earliest map of left hemisphere language organization and processing.

Methods of Assessing Lateralization

Lesion Studies

A good deal of what we know about language lateralization comes from studying the loss of language abilities following brain injury (Bear et al., 2007). Aphasia, the partial or complete loss of language abilities occurring after brain damage, is the source of much of the information on this subject (Bear et al., 2007). As shown in the studies of Bouillaud, Aubertin, Broca and Wernicke described above, lesion studies combined with autopsy reports can tell us a a lot about the localization of language, which ultimately has supplied information on lateralization. Lesion studies have shown that, not only is the left cerebral hemisphere most often dominant for language, but also that the right hemisphere generally is not, as lesions in the right hemisphere rarely disturb speech and language function (Bear et al., 2007).

The dangers of using lesion studies are, of course, that they may overemphasize the relevance of particular localized areas and their associated functions. The connection between brain regions and behaviours is not always simple, and is often based on a larger network of connections. This is shown in the fact that the severity of an individual’s aphasia is often related to the amount of tissue damaged around the lesion itself (Bear et al., 2007). It is also known that there is a difference in the severity of the deficit depending on whether the area was removed surgically, or was caused by stroke. This is the case because strokes affect both the cortex and the subcortical structures; this is due to the location of the middle cerebral artery, which supplies blood to the areas associated with language, as well as involvement of the basal ganglia, and is often the cause of stroke. As such, surgically produced lesions tend to have milder effects than those resulting from stroke (Bear et al., 2007).

File:Splitbrain.jpg

An example of a study involving language in a split-brain patient. The individual says he does not see anything, because the dominant left hemisphere cannot "speak". Image obtained from Experiment Module: What Split Brains Tell Us About Language

Split Brain Studies

Studies of patients who have had commissurotomies (split-brain patients) have provided significant information about language lateralization. Commissurotomy is a surgical procedure in which the hemispheres are disconnected by cutting the corpus callosum, the massive bundle of 200 million axons connecting the right and left hemisphere (Bear et al., 2007). Following this procedure, almost all communication between the hemispheres is lost, and each hemisphere then acts independently of the other. What is striking about split-brain patients with regards to the study of language lateralization is that a word may be presented to the right hemisphere of a patient whose left hemisphere is dominant, and when the patient is asked to name the word they will say that nothing is there. This is because, although the right hemisphere “saw” the word, it is the left hemisphere which “speaks.” If that same word is presented to the left hemisphere, the patient is able to verbalize the response (Bear et al., 2007). As such, split-brain patients have presented substantial evidence that language function is generally lateralized in the left hemisphere.

Wada test

The Wada test was created by Juhn Wada at the Montreal Neurological Institute in 1949, and was designed specifically to study lateralization. A fast-acting barbiturate such as sodium amytal is injected into the carotid artery on one side (although current procedures prefer to use a catheter which is inserted into the femoral artery), and is then transported to the cerebral hemisphere on the opposite side. It then serves to anaesthetize that side of the brain for approximately 10 minutes, after which it begins to wear off and the functions which were disrupted by the anaesthetic gradually return, often displaying aphasic errors (Bear et al., 2007; Wada and Rasmussen, 1960). During the time in which the patient is anaesthetized, he or she is assessed on their ability to use language. If the left hemisphere is anaesthetized and is the dominant hemisphere, the patient loses all ability to speak, whereas if the left hemisphere is anaesthetized but the right hemisphere is dominant, the patient will continue to speak throughout the procedure (Bear et al., 2007).

In a study published in 1977, Brenda Milner used the Wada test to demonstrate that 98% of right-handed people and 70% of left-handed people have a dominant left hemisphere with regards to language and speech function. Her results also showed that 2% of right-handed people have a dominant right hemisphere, which is the same percentage of patients that display aphasia following a lesion to the right hemisphere (Branch et al., 1964).

This procedure is also used prior to brain surgery in order to determine the dominant hemisphere, so as to avoid removal of an area associated with speech and language.

Functional transcranial Doppler ultrasonography

Functional transcranial Doppler ultrasonography (fTCD) is a non-invasive method for examining event-related changes in cerebral blood flow velocity in the middle cerebral arteries(Knecht et al., 1998). This technique can reliably assess which hemisphere is dominant and to what extent, which regards to language lateralization. Studies using fTCD have shown a linear relationship between handedness and language (Knecht et al., 2000).

Electrical stimulation, TMS and Imaging

Electrical stimulation was pioneered by Wilder Penfield and his colleagues at the Montreal Neurological Institute in the 1930s, and helped to identify certain lateralized areas associated with speech and language. Electrical stimulation is the application of an electrical current directly to the cortical tissue of a patient who is conscious. Penfield found that stimulating the left frontal or temporal regions of the left hemisphere with an electrical current accelerated the production of speech. He also found that stimulation can cause inhibition in complex functions like language, as applying a current to the areas associated with speech production in the left hemisphere while the patient is engaged in speech serves to disrupt this behaviour (Penfield, 1963). This procedure is performed during surgery while the skull is removed, and as such it is not a commonly used method of assessment.

Transcranial Magnetic Stimulation (TMS) is a non-invasive procedure, often combined in studies with MRI, which has helped to map the regions associated with speech, showing lateralization to be dominant in the left hemisphere. TMS has also shown that, following brain injury, it is more likely that it is the tissue surrounding the lesion that acts in a compensatory way rather than the opposite hemisphere providing compensation. The major drawback of TMS is, of course, the fact that the magnetic stimulation must pass through the scalp, skull, and meninges before stimulating the brain region of choice.

Imaging studies have proven to be incredibly useful in determining lateralization of language abilities. Functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) have been able to show the complex circuitry associated with speech and language; they have also proven to be consistent with the findings from previous lesion studies, as well as Penfield’s electric stimulation (Bear et al., 2007). There has been some controversy regarding bilateral activation shown in fMRI studies, the reasons unknown, however it has been suggested that perhaps the right hemisphere is involved in aspects of speech that are not measured by such tests as the Wada procedure (Bear et al., 2007). A significant finding is that fMRI results during developmental years show activation during speech and the use of language mainly in the left hemisphere, providing further evidence in support of left hemisphere dominance (Bear et al., 2007).

Cerebral Dominance: Language Functions of The Left and Right Hemispheres

The perisylvian cortex of the left hemisphere is involved in language production and comprehension, which is why it is often referred to as dominant, or said to "speak" (Ojemann, G. A., 1991; Purves et al., 2008). Roger Sperry and his colleagues’ split-brain studies have shown that the left hemisphere is also responsible for lexical and syntactic language (grammatical rules, sentence structure), writing and speech (Purves at al., 2008). Other aspects of language which are thought to be governed in most people by the left hemisphere include audition of language-related sounds, recognition of letters and words, phonetics and semantics.

The right hemisphere, though generally not dominant in terms of linguistic ability, has its role in the use of language. Split-brain studies present evidence that, despite the right hemisphere having no “speech,” it is still able to understand language through the auditory system. It also has a small amount of reading ability and word recognition. Lesion studies of patients who have right hemisphere lesions show a reduction in verbal fluency and deficits in the understanding and use of prosody. Patients who have had their right hemisphere surgically removed (hemispherectomy) show no aphasia, but do show less obvious deficiencies in areas such as verbal selection and understanding of metaphor. It has thus been concluded that the right hemisphere is most often responsible for the prosodic and emotional elements of speech and language (Purves et al., 2008).

Anatomical Asymmetries

The structural differences between the right and left hemisphere may play a role in the lateralization of language. In the nineteenth century, anatomists observed that the left hemisphere’s Sylvian fissure (lateral sulcus) is longer and less steep than that of the right (Bear et al., 2007). In 1980, Graham Ratcliffe and his colleagues used evidence of this asymmetry of the Sylvian fissure, shown in carotid angiogram, combined with results of Wada testing, and found that individuals with speech regions located in the left hemisphere had a mean difference of 27 degrees in the angle of the blood vessels leaving the posterior end of the Sylvian fissure, while those with language located in the right hemisphere had a mean angle of zero degrees.

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Asymmetry of the planum temporale. Image obtained from Labspace:Understanding Dyslexia

In the 1960s, Norman Geschwind and his colleagues at Harvard Medical School found that the planum temporale, the superior portion of the temporal lobe, is larger in the left hemisphere in almost two thirds of humans (Geschwind & Levitsky, 1968), an observation which was later confirmed with MRI (Bear et al., 2007; Purves et al., 2008). This asymmetry exists even in the brain of the human fetus (Bear et al., 2007). The correlation of this asymmetry with the left hemisphere’s language dominance is refuted by many due to the fact that 67% of people show this structural asymmetry, while 97% show left hemispheric dominance. Another problem which exists in examining asymmetry of the planum temporale is how the anterior and posterior borders of this region are defined, and the fact that investigators differ in this definition. This is especially a problem when the transverse gyrus of Heschl, used to mark the anterior of the planum temporale, appear in double (which is not unusual). There are differing opinions as to whether or not the second transverse gyrus should be defined as being within the planum temporale, or outside of it (Beardon, A. A., 1997).

Proposed Correlations

Handedness

The correlation between handedness and hemispheric lateralization is described in the results of the Wada test, described above. The majority of the population is right handed (approximately 90%), and the Wada test results propose that 93% of people’s left hemisphere is dominant for language (Bear et al., 2007). A linear relationship between handedness and langage has been shown using fTCD in a study done by Knecht et al. (2008); their findings show an 27% incidence for right hemisphere dominance in their group of left-handers, a finding consistent with the notion of there being a linear relationship between handedness and incidence of right hemisphere dominance in left-handers (Knecht et al., 2000). This study used a word generation task, and admits that perhaps a measurement of prosody or other such suspected right hemisphere functions may have a different relationship with handedness (Knecht et al., 2000). It is also true that correlation does not necessarily imply causation, and it is also suggested that there is no direct relationship between handedness and language at all, as the majority of left-handers also have their language lateralized in the left hemisphere (Purves et al., 2008). It is, however, a physical example of functional asymmetry, and it is certainly possible that a more substantial connection between handedness and language will be found.

Sex Differences

The tendency for women to score higher than men on language-related tasks is perhaps the result of the fact that women also tend to have a larger corpus callosum than men, indicating more neural connections between the right and left hemispheres. fMRI studies show that women have more bilateral activation than men when performing rhyming tasks, and PET studies show that women have more bilateral activation than men during reading tasks. Perhaps the bilateral activation implies the use of what are thought to be right hemisphere language abilities, such as prosody and intonation. Research has also shown that women have a greater ability to recover from left hemisphere brain damage; the evidence provided by the imaging studies in combination with the results of recovery following injury have led to the controversial suggestion that language is more unilateral in men than in women.

Sign Language and Bilingualism

Sign language has shown to be lateralized in the left hemisphere of the brain, in the left frontal and temporal lobes. This is known through the use of lesion studies, in which the patients had left hemisphere lesions in the areas associated with language which impaired their ability to sign, while right hemisphere lesions in the same areas show no linguistic deficit (Hickock et al., 1998). Lesions in the right hemisphere of signers did, however, show a limited use of spatial information encoded iconically (which is when the sign is similar-looking to its referent). This is in keeping with the belief that visuo-spatial ability is a right hemisphere function and suggests that the role of the right hemisphere in sign language is in the non-linguistic features of sign language.

Bilingualism is thought to be an overlapping of populations of neurons corresponding to each language, all of which are located in the frontal and temporal regions of the left hemisphere associated with speech comprehension and speech production.

Culture and Language Lateralization

When thinking of language there is a tendency to focus on that language in which you think, however it has been proposed that lateralization of language functions can vary from culture to culture. Asian languages show more bilateral activation during speech than European languages, likely because Asian languages employ a far greater use of right hemisphere abilities, for example prosody, and the use of spatial processing for the more “pictorial” Chinese characters; Native American languages also show a good deal of bilateral activity.

Reorganization following brain injury

Studies have been done following brain injury to determine the level of recovery of language and speech ability, and whether or not recovery is based on lateralized function. Bryan Woods and Hans-Leukas Teuber looked at patients with prenatal and early postnatal brain injury located in either the right or left hemisphere and drew several conclusions. First, if the injury occurs very early, language ability may survive even after left hemisphere brain damage. Second, they found that an appropriation of language regions by the right hemisphere is responsible for the survival of these abilities, but because of this there is a tendency for visuo-spatial ability to be diminished. Third, right hemisphere lesions have the same effect in prenatal and early postnatal patients as they do in adults. Brenda Milner and Ted Rasmussen used the Wada test to determine that early brain injury can cause either left, right or bilateral speech dominance, and that those who retained left hemisphere dominance had damage that was not in either the anterior (Broca’s) or posterior (Wernicke’s) speech zone. Those whose dominance shifted to the right hemisphere most often had damage to these areas. Milner and Rasmussen also found that brain damage which occurs after the age of 5 does not cause a shift in lateralization but rather reorganizes within the hemisphere, potentially employing surrounding areas to take responsibility for some aspects of speech.

In patients who have had hemispherectomy of the left hemisphere, the right hemisphere can often gain considerable language ability. When performed in adulthood, speech comprehension is usually retained (though speech production suffers severe deficits); reading capability is small, and there is usually no writing capability at all.

Learning Exercise: 8 Questions on Hemispheric Language Lateralization

1. In terms of hemispheric lateralization and split-brain patients (individuals which have had commissurotomies), if the word “pencil” was presented to the right field of vision of a split-brain patient and he/she was asked to report what they had seen, the patient would respond:

a) by selecting a pencil with the contralateral hand

b) by saying the word “pencil”

c) by saying “nothing is there”

d) by selecting a pencil with the ipsilateral hand

2. The left hemisphere is responsible for all aspects of syntax, except parsing. True or false?

3. What is the structural evidence given to explain the fact that women tend to score higher than men on language-related tasks? What implications might this have on gender differences in patients with aphasia?

4. What 3 conclusions did Bryan Woods and Hans-Leukas Teuber draw regarding the reorganization of language ability following brain injury? Would there be differences in such reorganization in people who are hearing impaired?

5. Through what anatomical system is the right hemisphere able to understand language? What happens to language ability following a removal of the right hemisphere? In what ways do individuals who have had their right hemisphere removed differ from split-brain patients?

6. What were the symptoms of the patient “Tan” which, when presented to neurologist Paul Broca in 1861, propelled Broca to his theory regarding hemispheric language lateralization? Based on current methods of assessment, would Broca's theory still be considered valid today? Why or why not?

7. Which type of study would be best used in order to assess anatomical asymmetry and why?

8. Which type of study is most useful in assessing the connection between hemispheric language lateralization and handedness, and why?

References

Beaton, A. A. (1997). The Relation of Planum Temporale Asymmetry and Morphology of the Corpus Callosum to Handedness, Gender, and Dyslexia: A Review of the Evidence. Brain and Language 60, 255–322

Bear, M. F., Connors, B. W., Paradiso, M. A. (2007). Neuroscience: Exploring the Brain, 3rd edition. Lippincott Williams & Wilkins: USA.

Branch, C., Milner, B., Rasmussen, T. (1964). Intracarotid Sodium Amytal for the Lateralization of Cerebral Speech Dominance. Journal of Neurosurgery, Vol. 21, No. 5, pp 399-405.

Clower, W. T., Finger, S. (2001). Discovering Trepanation: The Contribution of Paul Broca. Neurosurgery, Vol. 49, No. 6, pp 1417-1426.

Geschwind, N., Levitsky, W. (1968). Human Brain: Left-Right Asymmetries in Temporal Speech Region. Science, New Series, Vol. 161, No. 3837, pp. 186-187.

Hickok, G., Bellugi, U., Klima, E. S. (1998). The neural organization of language: evidence from sign language aphasia. Trends in Cognitive Sciences, Vol. 2, No. 4, pp 129-136.

Jay, T. B. (2003). The Psychology of Language. Prentice Hall: New Jersey, USA.

Knecht, S., Deppe, M., Ebner, A., Henningsen, H., Huber, T., Jokeit, H, Ringelstein, E.-B. (1998). Noninvasive Determination of Language Lateralization by Functional Transcranial Doppler Sonography : A Comparison With the Wada Test. Stroke, Vol. 29, pp 82-86.

Knecht, S., Deppe, M., Drager, B., Bobe, L., Lohmann, H., Ringelstein, E.-B., Henningsen, H. (2000). Language lateralization in healthy right-handers. Brain, Vol. 123, pp 74-81.

Kolb, B., Whishaw, I. Q. (2009). Fundamentals of Human Neuropsychology, 6th edition. Worth Publishers: USA.

Ojemann, G. A. (1991). Cortical Organization of Language. The Journal of Neuroscience, Vol. 7, pp 2281-2287.

Penfield, W. (1963). The Brain's Record of Auditory and Visual Experience. Brain, Vol. 86, No. 4, pp. 595-696.

Purves, D., Augustine, G. J., Fitzpatrick, D., Hall, W. C., LaMantia, A., McNamara, J. O., White, L. E. (2008). Neuroscience, 4th edition. Sinauer Associates, Inc.: Massachusetts, USA.

Wada, J., Rasmussen, T. (1960). Intracarotid Injection of Sodium Amytal for the Lateralization of Cerebral Speech Dominance Experimental and Clinical Observations. Journal of Neurosurgery, Vol. 17, No. 2.

In addition, actions focused on threatened language speakers (appreciation of ethnic belonging, community educational actions, etc.), it is important to act at the political level. To convince the State to promote official policies of valorization and expansion of the functions of the language, of use in school spaces, in public offices. See the case of Brazil at www.ipol.org.br.

One of the means used to promote Zenet is school, both formal and informal. The problem is that the books and programmes are based on Berber-Kabylian which, although members of the same Tamazight family (Hamito-Semitic) as Zenet, are quite different from it. What is interesting is that Tamazight is taught even in illiteracy-eradication schools here in the south of Algeria.

This is about applied linguistics which concerns reactivating our initial language which is the mother tongue by teaching, communicating with one another. Though, the pressure of colonization was too much.

Many Caucasus languages got their "second" life by implementing writing system and recently by broadcastings on radio

@AleksandrMaryukin

The same is done here in Adrar south of Algeria, where Tamazight is broadcast through local radio and taught at both formal n informal schools

The process of revitalizing and promoting endengered languages is linked to education . Schools are a good platform for such languages teo be more visible bacuse of the writing system procedure they will be put in. The speech community as well has to be part of that process through radio, tv shows, etc. However, the political will to see them used in administration and institutions could be of a great advantage.

@Ludwine you r right and I agree with you. Unfortunately the political will is the most difficult to obtain so as to revitalise an endangered lge variety.

I agree, Ludwine. Those were all critical in the revival of Welsh.