The Role of Critical Period in Second Dialect Acquisition - Essay Example

Revisiting the Critical Period Hypothesis for Language Acquisition Table of Contents Revisiting the Critical Period Hypothesis for Language Acquisition 1 I.Introduction and Overview 3 II.Evidence Supporting a Critical Period Hypothesis 4 III Evidence against the Critical Period Hypothesis 5 IV Second Dialect Learning 10 V. Conclusions 11 References 13 I. Introduction and Overview The critical Period Hypothesis was proposed publicly in 1967 by Lenneberg (1967), and linguistic and language researchers have been trying to prove or disprove this ever since. It has proven a difficult task to even define what is meant by CPH and where and how it might apply. It was originally framed for an explanation of first language acquisition and why it was difficult or impossible after a certain age. It was hypothesized that after a certain age, usually deemed to be around puberty, if a first language had not been acquired, it would be difficult, or impossible, to do so. At the time there had been enough discovery of a number of feral children to support this hypothesis. However, other variables were problematic, as these same children had been neglected, deprived and usually abused. Many were half starved and most had suffered isolation. With all these factors involved it was difficult to limit the variables in order to establish cause and effect. Later, other linguists tried to tie this theory also to second language acquisition with varying contradictory results. Finally, neurobiologists did manage to identify a portion of the brain that seems not to develop if a “second” language is not acquired by a certain pivotal age, generally coinciding with puberty. However, just what exactly is meant by a second language is not cast in stone. Does Latin qualify? What about children’s code language for play? Do other jargon sets qualify, such as mathematics terminology, psychology vocabulary or academic English? What about a second dialect sufficiently different from the mainstream language? Little or no research has been done with these languages as the “second language” acquired, so it is still unanswerable. However, it is this researcher’s suggestion that perhaps any sufficiently large complex symbolic system will fill this void. However, in the case of a dialect, if the first language is a dialect of the mainstream language, is there a critical period beyond which it becomes problematic for the learning of the mainstream language? II. Evidence Supporting a Critical Period Hypothesis Lenneberg first hypothesized the existence of a critical period for language learning in 1967, and it was supported by the case study of Genie, who had little or no exposure to language until age sixteen. He hypothesized that “language acquisition is impossible before two due to maturational factors, and after puberty because of the loss of ‘cerebral plasticity’ caused by the completion of the development of cerebral dominance, or lateralized specialization of the language function.” There are case studies dating back to Carl Linneaus’ Homo Ferus in his book Systems of Nature, and there have been many more cases documented since the case study on Genie in 1972 (Fromkin and Krashen et al., 1974, pp. 81-107). The cases documented by Fromkin et. al. support the theory of a critical period, but there are other circumstances in each and every case that make it impossible to isolate the one variable of language exposure as causal. In each case the other variables could certainly impact the ability to learn language very strongly. Andrew Schouten (2009) noted that there was simply not sufficient evidence to support the critical language hypothesis for first language learning due to the circumstances discussed by Fromkin (1974). Schouten did note that Bleyvromman’s Fundamental Difference Hypothesis in 1988 supported the hypothesis for second language learning, but that Krashen’s research supported a weak critical period hypothesis for second language, saying that Krashen had proven that there were exceptions and hypothesised that this was due to the adult learner’s provision of modifying factors, such as intensive study or immersion in the language environment. This is supported by Vanhove: In its most general version, the CPH for SLA states That the ‘susceptibility’ or ‘sensitivity’ to language input varies as a function of age, with adult L2 learners being less susceptible to input than child L2 learners. Importantly, the age–susceptibility function is hypothesised to be non-linear. (Vanhove 2013) III Evidence against the Critical Period Hypothesis Early researchers had supposed a lateralization of the brain function during or after the critical period, but this cannot be shown to be the case in second language acquisition. Lenneberg’s Critical Period Hypothesis may be true for individuals not exposed to language at all before about puberty, as the brain lateralization was evident in Genie and other cases, but in those cases the cause could not be definitively isolated, and in second language such lateralization does not appear to be a given (Klein, Mok et al. 2013). There is proof of brain change after language acquisition, and especially after second language acquisition in the frontal cortex, a balancing of the hemispheres, with one side thinning and the other thickening (Klein, Mok et al. 2013). However, this does not seem to affect the lateralization of processing. A study by Kim, Relkin Hirsch differentiating second language learners who learned the second language in childhood parallel to their first language show that both Wernicke’s Area in the back of the brain which seems to process meaning, and Broca’s area in the left frontal cortex while participants were asked to think in each language. The participants that learned the two languages early used the same part of Wernicke’s area, but the adult second language learners used a different part of Broca’s Area (Kim, K. H. S., Relkin, N. R., Lee, K. M., & Hirsch, J. 1997). Kim and Hirsch looked specifically at two language centres in the brain--Broca’s area, in the left frontal part, which is believed to manage speech production, and Wernicke’s area, in the rear of the brain, thought to process the meaning of language. Both groups of people, Kim and Hirsch found, used the same part of Wernicke’s area no matter what language they were speaking. But their use of Broca’s area differed: it was near the area used for the first language, but not the exact same area. Further study posits that Broca’s Area is for language making, while Wernicke’s area is for receiving communication. A study using 120 bilingual (English and Welsh) participants in four distinct groups sheds further light upon this issue. The study separated participants by age and environment. There was no difference between early and late learners of the second language who were from a dual language environment, but with participants who learned Welsh later in an English environment the right hemisphere was involved (Ekiert 2005).This flies in the face of an age limitation on second language learning to near native level, but it does support immersion as a very favourable aspect in teaching. Johnson and Newport’s (Johnson, Newport 1989) study of Korean and Chinese immigrants showed a correlation between age of English acquisition in the US English environment, but there are some problems with the validity of these results also. There is no information concerning the immersion factors, so there is no proof that the children did not have more exposure to English by virtue of school attendance. In addition, the difference among languages is likely a learning factor in second language acquisition. Andrusyshyn (personal interview, because the study was only published in Chinese by the school involved) states that Chinese learners of English in China when living in an English environment can acquire near native proficiency. This was tested in two ways. A group of students voluntarily created a totally English environment or nearly six months by using only English outside of class (even in public, as Chinese speakers cannot hear a Chines accent on English), watching only English movies and TV, reading English novels and textbooks, and setting English as the language in Internet browsers and writing emails etc. in English. The second method used involved directing the school supplied teaching assistant to stand at a whiteboard during class and when she noticed anyone looking confused she was to write the Chinese characters for what was being said. Andrusyshyn (2011) deliberately inserted more difficult words in selected places during class in order to see the difference. A parallel class without the teaching assistant with students of similar age and level showed less progress over four months of study. A supporting study with 240 Korean immigrants into the US supports the hypothesis that exposure level is critical and that there is a subtle different in how English is learned with persons from non-alphabetic language groups (Flege, Yeni-Komshian and Liu, 1999). In looking at the charts from Flege there are some interesting results there that correlate with information obtained by this author. The ages at which the participants in this study arrived in the US is listed, and there is a definite decline in learning at age ten, which is the age at which most students in Korea, China and some other countries begin English language study in their own countries. This is because it is consider necessary for the students to have full use of their native language before adding a second language to instruction. This is the same in the province of Quebec for French students, which is why it was noticed by some Canadian friends who taught in Asia. So many students under ten years old would not have had much exposure to English. More important, their native language will have, presumably, become solidly entrenched, including the lack of tenses, the particular set of phonemes and the visual character of the language. In English, the meaning is carried in the sound, and the writing is a symbol of the sound. However, in most Asian languages, particularly Mandarin and Korean, the meaning is carried by the writing and the sound is a symbol of the writing. In looking at the charts from Flege et. al. (1999), the drop off of scores is right around ten years old for native Koreans for foreign accent rating, perhaps because there is a time after which we do not add new phonemes to our language. Young children can mimic nearly any phoneme, but they gradually eliminate those which do not get them what they want or need, keeping only those used in their language. If a second language is added soon enough, they may still have those phonemes in memory somewhere, and then these will also be retained. However, those which are not used may gradually be eliminated and then have to be added back in if they are needed. There seems to be a slower loss of ability to learn grammaticality and more retention at older ages. However, this chart shows that the young ones have a greater retention. Again the language of origin may be partly responsible, since the grammar of the two languages is very different. The next pair of charts is interesting in light of the idea that pronunciation is one area in which most studies found that there is a permanent loss of ability after about puberty. The Critical Period Hypothesis appears to be valid for the ability to attain accentless proficiency. Since this test was given using audio, there may also be an inability to hear certain syllables used to change English function words, like nouns and verbs, making singular and plurals, past and present sound alike. The chart on the right shows interesting patterns for lexically versus rule based language skills. The rule based fall off in a gentle curve where-as words based stay steady until after age ten and then fall off in a steep curve, but they then stabilize at around age eighteen and stay at that level. Rules are not remembered as well as patterns perhaps. This seems to indicate that there is more going on than a simple theory, such as the Critical Period Hypothesis can explain. Johnson and Newport (1989) did modify the early version of the Critical Period Hypothesis in that they showed that there is no exact cut-off point for language learning and that post-pubescent learners who studied a second language could still acquire near native proficiency with practice and this seemed to keep the ability to learn further language available throughout life. There is some indirect evidence that adult learners will have an accent and in consideration of supporting materials, most researchers agree that there is a child advantage for acquiring phonology (though it may not be a maturational one, but rather may be connected to tuning the ear to certain phonemes and Wernicke’s area (Snow & Hoefnagel-Hohle, 1977, Olson & Samuels, 1973). Johnson and Newport cite Long (1990) and Patowsky (1994) as having stated that pre-puberty exposure to the second language is necessary if a near native accent it to be achieved, and Scovol (1988) who insists that pronunciation is the only area where early exposure is necessary, because it is the only area that has a neuromuscular basis (p101). IV Second Dialect Learning There is really not a lot of useful research in second dialect study, and even less as relates to the Critical Period Hypothesis. There has been research in French in some countries, and a few involving Pidgin versus standard English, but there was nothing to be found concerning a Critical Period Hypothesis. However, some of the research in the United States on inner city black cultures, particularly those which speak a version of English termed Ebonics that seems to have some interesting information. What is in the literature seems to pertain to minor grammatical differences, some vocabulary differences and accent or pronunciation. “Schmidt claims that language learning cannot take place unless students consciously and specifically notice the form of the input and compare it to their output. Once this ‘gap’ has been observed, it serves as a priming device (Gass,1997; Oliver, 2009), setting the stage for further learning.” (Flege, Yeni-Komshian and Liu, 1999) Even in the few studies of US Black dialect (Ebonics), the major area discussed was pronunciation and a few variations on irregular verbs that seem problematic even for fist language learners. First language learners use the Danish origin auxiliary verbs and the verbs “to be” and “to have”, but they do not really understand the rules. They do not match most of the other verbs in the language. One study on African American English dialect investigated the developmental differences in reading and the pathway of progress toward mainstream English use(Goodman, Buck 1997). Another journal article looked at pronunciation, learning mainstream style and the possibility of discrimination (Pearson, Velleman et al. 2009). None of these or any of the other 14 articles examined on various second dialect learning mentioned The Critical Period Hypothesis. However, it bears mentioning that since most of the work being done on second dialect learning emphasises pronunciation and accent, it stands to reason that there is probably a Critical Period during which the perfection of the second dialect is easier and more certain, since it is linked with sound input and output, not meaning. V. Conclusions There is a whole long list of other studies, but most cite these major researchers in their conclusions. The result is mixed, but there seems to be sufficient evidence that though there is a neuro-biological difference among language learners that separates early bilingualism from late, and that separates immersion levels, there is no age cut-off for the ability to acquire proficiency near a native speaker of a second language. While there is evidence that the eventual proficiency attained declines after puberty, there are no causal links. There is also no sharp sudden drop in the ability to learn a second language. There is evidence that learning at least one second language does make changes in the brain and that early bilingualism versus late results in a different use of Brocaw’s Area and different processing. Also, there is evidence that early exposure to the learned second language impacts the accent strength. Early exposure seems to result in a better accent, while learning one additional language before puberty seems to make a difference in attainment. However, immersion can counteract the effects of late learning very well, and motivation and auditory feedback seem to enhance second language learning at a later age. Also, early exposure to various languages even in part will tend to result in the retaining of the ability to use the phonemes of the target second language. For example, French contains two major sounds not found in English: the sound of “eu” as in “un peu” and the sound of the French “r” which is produced at the back of the throat involving the rear of the tongue and the uvula, plus a slight fricative factor in some geographical areas. An even more difficult “r” is used in Mandarin Chinese in Beijing, which employs a very fricative slightly voiced “r” produced in a manner similar to the French. These sounds do not occur at all in English, so without early exposure they may be eliminated from the memory and the speaker may even have difficulty hearing them, much less reproducing them. Finally, when considering the hypothesis in relation to learning a second dialect it may have a strong effect, since it appears that Wernicke’s Area is involved in the differences in beginning learning after puberty. It should be understood that most of the literature emphasises the pronunciation of different dialects over grammatical and vocabulary differences. We appear to be able to add new words throughout life, and even learning new grammar is not that difficult for most people of average intelligence, but perfecting a particular second dialect accent may be subject to problems caused by the passage of the critical period for learning new phonemes. References Andrusyshyn, K. 2010. 不教英语教英语 (Teaching English without Teaching English) Xi Yi Elementary School, Beijing (Internal publishing only). Ekiert, M., 2005. The bilingual brain. Teachers College, Columbia University Working Papers in TESOL & Applied Linguistics, 3(2),; available at McGill University. "Learning a new language alters brain development." ScienceDaily. www.sciencedaily.com/releases/2013/08/130829124351.htm (accessed April 16, 2014). Flege, J., Yeni-Komshian, G. and Liu, S., 1999. Age constraints on second-language acquisition. Journal of memory and language, 41(1), pp.78--104. Goodman, K.S. and Buck, C., 1997. Dialect barriers to reading comprehension revisited. Reading Teacher, 50(6), pp. 454. Johnson, J.S. and Newport, E.L., 1989. Critical period effects in second language learning: the influence of maturational state on the acquisition of English as a second language. Cognitive psychology, 21(1), pp. 60-99. Kim, K. H. S., Relkin, N. R., Lee, K. M., & Hirsch, J. (1997). Distinct cortical areas associated with native and second languages. Nature, 388, 171-174. Klein, D., Mok, K., Chen, J. and Watkins, K.E., 2013. Age of language learning shapes brain structure: A cortical thickness study of bilingual and monolingual individuals. Brain and Language . Lenneberg, E. H., Chomsky, N. & Marx, O. (1967). Biological foundations of language. New York: John Wiley & Sons. Pearson, B.Z., Velleman, S.L., Bryant, T.J. And Charko, T., 2009. Phonological Milestones for African American English-Speaking Children Learning Mainstream American English as a Second Dialect. Language, Speech & Hearing Services in Schools, 40(3), pp. 229-244. Vanhove, J., 2013. The Critical Period Hypothesis in Second Language Acquisition: A Statistical Critique and a Reanalysis. PLoS ONE, 8(7), pp. 1-15.   Read More