You may be interested in reading "Language as a Complex Adaptive System" (2009) by N.C. Ellis and D. Larsen-Freeman. This book made me think a lot of issues in SLA. My opinion is that there have been abundance of research interest and research works but little consensus has been achieved. I thought that the perspective of viewing language as a complex adaptive system may offer us a reason why it has been like that.

Recently, I was reviewing literature on lexical learning. My task was to make a state of art recommendations on lexical learning strategy and teaching method for foreign language teachers and learners. Then I realized how messy the findings are. A simple statement like "vocabulary learning within context is more effective than learning in isolation" does not go farther without encountering a counter-claim. In fact, lexicon is complex in its composition and very much adaptive as it creates a new member all the time. Perhaps, there is a type of words that can be readily learned in isolation while there is type of words that can be better learned within context (Subtirelu, 2013). The researchers often overlook the fact that lexicon is very much heterogeneous in its composition. Lexicon is not a collection of the same type of information. I believe the Complex Adaptive System (CAS) or Chaos/Complex (C/C) approach can sort a number of conflicted study findings in SLA.

Dear Heejong. Thanks for you contributuion and reply.

I recommend you to read the work "Chaos and language" (2004) by W. Garrett Mitchener and Martin A. Nowak, published in Proc. R. Soc. Lond. B (7 April 2004), vol. 271, no. 1540, pp. 701-704. (doi: 10.1098/rspb.2003.2643)

I reproduce below the abstract of their work:

"Human language is a complex communication system with unlimited expressibility. Children spontaneously develop a native language by exposure to linguistic data from their speech community. Over historical time, languages change dramatically and unpredictably by accumulation of small changes and by interaction with other languages. We have previously developed a mathematical model for the acquisition and evolution of language in heterogeneous populations of speakers. This model is based on game dynamical equations with learning. Here, we show that simple examples of such equations can display complex limit cycles and chaos. Hence, language dynamical equations mimic complicated and unpredictable changes of languages over time. In terms of evolutionary game theory, we note that imperfect learning can induce chaotic switching among strict Nash equilibria."

I recommend you to read their full paper!

ok, the question makes no sense to me as it starts with a proposition that I could not find any evidence of. The Question starts with the following statement "In the past, it was believed that the nature of languages like any other systems are constant and static". There seems to be quite a lot of work (predating the current discussion on "complex systems") suggesting contrary, for example the work of Wittgenstein, who coined the concept *languaging*. But he was not the only one with relevant work related to this question. There is also a lot of work within the area of cybernetics and systems science. If nothing else the work of Gregory Bateson comes to mind (for example in the book *an ecology of mind*).So the question itself may need some further work.

Dear Peter, would you please suggest the right question. That will be very kind of you.

I find this topic interesting, and I am reading papers on it.

One interesting paper is "Chaos, complexity and language learning" by Bill Harsharger published recently in "Language Research Bulletin". It is a general paper only.

I already mentioned another interesting paper "Chaos and language" by W. Garrett Mitchener and Martin A. Nowak (2004). There is a nice mathematical model in this work and the authors explain well that language dynamical equations mimic complicated and unpredictable changes of languages over time.

Thank you very much dear Sundarapandian for your contribution and response. It is very pleasant that the question interests you to follow the topic.

The whole foundation for the question maybe needs some revision. So for example it is questionable to state that "In the past, it was believed that the nature of languages like any other systems are constant and static" - there is little (if any) evidence that this proposition is correct when there are many sources suggesting otherwise (examples mentioned above). Then the proposition continues with "however after several years of study and with reference to the Chaos/Complexity theory (C/CT), they came to the conclusion that languages are complex, nonlinear and unpredictable in their underlying levels." It is perhaps the case that specialism within areas of scientific inquiry can make people blind and unaware of previous work which their own environment does not readily know about. Ignorance of other peoples work does not however mean that such work did not exist. It is not at all obvious why the reference should limit itself to Chaos/complexity theory (whatever that is supposed to be refering to - considering there is more than one proposition with similar sounding name and theoretical descriptions but with significantly different foundations and *meaning*). Even similar descriptions may have very different knowledge and practical consequences dependent on which *philosophy of science* they may be associated with (and by whom). So yes we could agree upon that there are issues in SLA that can be illuminated by the chaos/complexity theory. But we would need to explore and have a dialogue about - what - do we mean with *chaos/complexity theory* and - what - do we mean with *issues*. Perhaps also the purpose of our inquiry and why we are interested in SLA needs to be reflected upon.

Dear Peter, thanks for your contribution. That is a nice question posed by you: what - do we mean with *chaos/complexity theory*, I've raised this question to get the responses for it, Could you please think aloud and answer/elaborate your own question?  

Perhaps we would benefit from first asking ourselves what issues we can identify with SLA? As it might help us with creating *a purpose* for our engagement with (other) theories and traditions such as those drawing upon ideas of *chaos and or complexity*... What issues - or - what kind of issues - do you have in mind, when thinking of SLA?

Dear all, very interesting discussion! I think the essence of Complexity / DST approaches to language development is the time dimension. Although I agree with Peter that we cannot say all previous thinking about SLA has been essentially static, the real focus on change over time is relatively new. Rather than looking at factors that may have affected the products of language learning, it is time to really start looking at the process of development and the complex interrelation of changing factors over time. On refs: We (Kees de Bot, Marjolijn Verspoor and myself) published on this in (eg) Bilingualism: Language & Cognition, and Marjolijn and I have just finished a paper on the time dimension of SLD and the fact that this requires different (ie longitudinal) research paradigms - this will come out later this year in Language Learning.

I agree with Peter when he said Chaos/Complexity theory does not necessarily propose  nonexistent hypotheses; however, considering the fact that the term " Language as a complex adaptive system" is an all-inclusive and illuminating terminology, one can justify that the recent literature on the dynamic and complex nature of language development/ change/ acquisition/ learning can be acceptably accounted for by the new PARADIGM of Chaos/Complexity theory in our field.

I believe soon enough this PARADIGM will be included in the development of TESOL==) Behaviorism, Cognitivism, Constructivism, Humanism, Dynamic complex systems theory...

As an example, dynamic assessment can be put under the paradigm of Dynamic complex systems theory. It can and should also be worked on so as to account for the principles of this paradigm.

Don't hesitate to ask professor Lowie about Chaos/Complexity theory. His papers speak for themselves.

Complex Systems Theory can be brought to bear on several aspects of instructed language learning/language acquisition. Some approaches include attempts to reconceptualise language as a complex system, while others have approached this by applying complexity on the psychological aspects of language acquisition, or by thinking of educational settings where language learning takes place as complex systems. It has also been suggested that Complexity can be used to 'bridge' different, yet compatible, theoretical perspectives that have informed the discipline.

While complexity is a promising new paradigm for Applied Linguistics, there are some challenges to be faced. For instance, it seems that transferring Complex Systems Theory without modification from the natural sciences to SLA/Applied Linguistics is not the best way to go. Rather, it appears that we need to 'nativise' it, and this begs the question of how far we can stray from the original theory to suit our purposes, while still claiming to work in the domain of Complexity. 

If your are interested in exploring the literature, an obvious starting point would be Larsen-Freeman & Cameron's (2008) Complex systems and Applied Linguistics, and the Special Issues in Applied Linguistics (2006) and the Revista Brasileira de Linguistica Aplicada (2013) [it's in English]. Some names to look out for are: Diane Larsen-Freeman, Lynne Cameron, Sarah Mercer, and some of the more recent work by Zoltan Dornyei. If you come across anything I have written on the topic, that ,too, may be of some use.  

I liked the part that dear Achilleas said " how far we can stray from the original theory to suit our purposes"

Unfortunatly whenever some theory becomes a paradigm in our field, it seems like everyone goes out of his/her way to necessarily adapt most of the findings of applied linguistics to that paradigm. That's why, as a student, I have been being annoyingly surprized by what D. Brown calls "changing winds and shifting sands" of language teaching.

I believe those who have voice in our field must let this process takes its course and there is no need for rushing it. It's not like anyone can by any chance precede them in any idea!