When one has a cold, the voice becomes more nasal. In India, in the state of Kerala, the words are so rich with nasal phones that over the years, their voice itself has become nasal. So, the relative level of nasality can also characterize someone's voice. So, the question is, are there signal processing techniques that extract features from speech, which are correlates for nasality?
The term "nasality" is too general. This falls under the heading of "resonance" and can mean hyper- or hypo- nasality, among other things. Hyponasality is when you have a cold and a congested nose. Hypernasality is when too much air comes out the nose, such as cleft palate speakers, some neuromuscular weakness patients, etc. The trained listener is the best test, but there are objective tests also that are commercially available. These include "nasalance" and "rhinomanometry" testing. You can look these up easily. Both have significant shortcomings.
I hope this helps.
Dear Dr. Sidman,
Thanks for your kind reply, through which I came to know that there are instruments for clinical measurement of nasalance, etc. However, what I am looking for are methods that simply pick up the net speech through a single microphone and analyze it to quantify the (say) percentage hypernasality in someone's voice, which I can use as an additional feature to identify a person (speaker identification).
Regards
AGR
Check out the work of Tarun Pruthi or Carol Espy-Wilson (University of Maryland).
Best,
Sona
Thanks. I got the thesis of Tarun under the guidance of Espy Wilson.
No problem. I would be interested to know whether you find his methods useful for your purpose. I haven't really heard of nasality detection sensitive enough for normal speech (at least when I checked about 5 years back).
Best, Sona
Yes. You can measure nasality and there are signal proxessing techniques. In particular Nasality is an aspect of voice “quality” traditionally assessed by the perceptions of professionals involved in the evaluation and treatment of resonance disorders. However, despite the importance of an expert’s perception of the absence, or presence and degree, of nasality to the evaluation process, there is also a need for objective measurement.
For this purpose clinical instruments like the Nasometer has provided an easy method for assessing nasality objectively.The nasality measure is derived from the ratio of acoustic energy output from the nasal and oral cavities of the speaker. Using an innovative input device consisting of a directional microphone mounted on either side of an efficient sound separator plate (with 25 dB separation between channels), the Nasometer headset facilitates accurate signal analysis, which ultimately yields a “nasalance” score. As the speech signal enters the system, the ratio of the nasal acoustic energy to the oral plus nasal acoustic energy is calculated in terms of percentage (i.e., (N/(N + O)) x 100 = Nasalance) and is displayed graphically on the host computer screen in real time.
You can find more details in the following link. Do not hesitate to contact me for any more details.
I hope this is useful.
Best Eugenia
http://www.kaypentax.com/index.php?option=com_product&controller=product&Itemid=3&cid[]=78&task=pro_details
I know this question was asked long ago.
I came across this now.
I just want to acknowledge work done on nasalence / objective analysis of nasality at All India Institute of Speech and hearing , Mysore since 1980s. Recently its unit on cleft palate also has published some interesting information.
Dear Prof. Suresh Thontadarya ,
You say that AIISH has worked on it; can you point me to one or more of their good publications, where I get a technique for robust estimation of nasality?
Dear Dr A G Ramakrishnan, Much of work done at AIISH are available as proceedings of workshops, dissertation etc and may not be accessible to others directly. One can contact Faculty members there for such information.
I can list out few which are Probably relevant to you and available through journals...
1. Yeshoda, K. (2007). Perceptual Cues of Nasals. Proceedings of the National Workshop on Phonetic Perception, AIISH.
2. Gnanavel, K., GopiSankar, R., & Pushpavathi, M. (2013). Normative nasalance values across stimuli and gender in Malayalam speaking individuals. Otolaryngology, Vol. 3 (4).
3 Navya, A. & Pushpavathi, M. (2017). Correlation of Perceived Nasality with the Acoustic Measures (One Third Octave Spectral Analysis & Voice Low Tone to High Tone Ratio). Global Journal of Otolarynglology, 8(3), 1-6.
Hope this helps, If you need additional information, i can forward contact details of faculty members who i know ...Regards
Dear Dr. A.G. Ramakrishnan
As previously mentioned by Eugenia I Toki, Nasometer is a widely used instrument to record the speech samples' nasality and/or nasalence. Also, as mentioned by Himanshu Kumar Sanju, the therapeutic module of Vaghmi Software (By Voice and Speech Systems, India) offers the facility of assessing nasalence. If you are looking for research studies done on nasal resonance, AIISH digital repository has several project reports, theses, and PG dissertations uploaded. Much of the work is done in the area of assessment and treatment of persons with cleft lip and palate. You can also find studies reporting the Normative Nasalence values in different Indian regional languages like Hindi, Kannada, Manipuri, etc.
You can use this link to connect to AIISH digital repository: http://203.129.241.86:8080/xmlui/
You can find the resources I mentioned under the institutional repository tab. Prof Suresh Thontadarya already mentioned different studies that you could refer to. Adding on a few other major works to that list here:
1. Objective measurement of Nasality. (1989) Sarguna Murthy – PG dissertation
2. Normative score of nasometer in Kannada (2005) Jayakumar T – PG dissertation
3. Correlation and reliability of nasalence distance, nasalence ratio and mean nasalence value (2013) Bhutada Ankita Murlidhar – PG dissertation
4. Some Acoustic and Perceptual parameters of cleft palate speech: A pre-post operative condition (2016) Gopi Shankar R – Doctoral Thesis
5. Construction of Nasality Severity Index (2016) Navya A – Doctoral Thesis
6. Validation of Nasality Severity Index (2016) Navya A, Pushpavathi M – Funded project
7. Relationship between nasalence and AVQI (2020) Reshma O – PG dissertation
Hope you find this information useful.
Regards,
Revathi
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