Critical Period Hypothesis

I was a little surprised to discover at first just how controversial the idea of a CPH or “sensitive period” is in second language acquisition. After reading the articles, however, there appears to be little disagreement that younger language learners generally outperform adult beginners in the long run, and that it is common for child beginners to acquire native or near native proficiency in an L2 while it is rare or unattested for adult beginners (Marinova-Todd et al. 2000 p11). Most of the disagreement seems to be on what factors explain the general success of child learners and general failure of adult learners to acquire near native levels of proficiency and competence. The CPH and SPH are biological explanations while others such as Flege (1987) point to differences in affective and situational factors as an alternative explanation.

I am a little skeptical that affective and situational factors alone could account for the linear correlation between age of arrival and proficiency of children and the variability and lack of correlation for age of arrival and proficiency shown in studies such as Johnson and Newport study (Brown and Gonzo 75-112). It seems unlikely that children uniformly experience similar affective and motivational characteristics which lead to their success while different affective factors lead to general failure and invariability in adult populations. It would seem likely that there are many adult second language learners with high motivation who are less fearful of taking risks while there are many children who may have low motivation and are more fearful of making errors in production.

Anecdotally I have several friends, mostly Arabic speakers, who began learning English as adults, and who are married to non-Arabic speaking Americans, speak only English at home and work, and who appear to be highly motivated language learners. Despite the fact that they have lived here for a decade or more and are very proficient English speakers, they cannot pass for native speakers.

Whether or not there are biological maturational constraints on second language learning I found that it was difficult to make comparisons between the different articles assigned for class. For example the Flege article examined phonological aspects of L2 learning in both perception and production, the Johnson and Newport study looked at the ultimate attainment of grammatical competence (not performance), and the Wang and Kuhl article looked at the rate of attainment between children of different ages and adults in the perception of Mandan tones after a period of instructed learning. The problem with comparing these different approaches is that they are looking at different aspects of language and language acquisition. It is possible that there is a difference between instructed and naturalistic learning, so that the results of a study such as Wang and Kuhl may not be generalizable to a population which has learned in a more unstructured environment. That there is no difference or a difference which favors adults in more structured environments is not necessarily evidence against the Critical Period Hypothesis. It would just show that adults are more adept in more structured settings. Another problem with the Wang ad Kuhl study is that they are looking at the initial rate of learning and not the ultimate attainment of the learners. According to the Marinova-Todd et Al. article this distinction has been recognized with regard to the acquisition of morphosyntax for some time, citing the Krashen et Al. review (1979) which showed that older learners initially acquire a language faster than child learners, but that the younger learners will eventually attain greater proficiency levels. (Marivona-Todd et Al. P 12) In addition to this study the Flege article cites a study by Snow and Hoefnagel-Hohle which showed that adult accents may be judged more accurate than a childs after a short period of learning, but that the reverse is true after a longer period.