target language was chosen because, unlike English and Dutch, it is not a Germanic language, and because it is less often encountered over the Dutch airwaves than English. Over a range of performances, and again using strict criteria for nativelikeness, 3 of 9 highly proficient late learners of French were judged to be indistinguishable from natives.
Bialystok and Hakuta grant that for L2A, earlier is better, but stake out the position that it is misguided to infer a causal relation between age and attainment. Rather, Bialystok and Hakuta liken age to an intervening variable in a design; were it to be controlled for experimentally or partialed out of a regression equation, then one would find linguistic factors and cognitive factors at play. The linguistic variable is exemplified in native-language transfer. If there is a change in the language acquisition mechanism over time, then what is transferred from the Ll to the L2 should also change: Early on, more abstract UG constraints should transfer, while later learning should be characterized by relatively more transfer of L1-specific surface features. A review of the relevant literature suggests that this is not the case. With respect to cognitive factors, Bialystok and Hakuta argue that literate versus nonliterate populations differ in ultimate attainment. This, along with the authors' demonstration of proficiency differences as a function of educational level, cannot be captured by a simple maturational account of L2A. Bialystok and Hakuta also argue that the declines in general cognitive abilities that come with aging, being gradual and linear, are a better fit with the L2A data -- which include the authors' report of a large-scale survey of immigrants to the United States -- than is a critical-period-type function which, arguably, should exhibit some form of discontinuity.
Each of these chapters, whether anti- or pro-CPH-L2A, illustrates the richness, depth, and breadth of critical period inquiry. Collectively, they testify to the unmistakable centrality of the CPH in L2A research.
Bever, T. G. ( 1981). Normal acquisition processes explain the critical period for language learning. In K. C. Diller (Ed.), Individual differences and universals in language learning aptitude (pp. 176- 198). Rowley, MA: Newbury House.
Bialystok, E., & Hakuta, K. ( 1994). In other words: The science and psychology of second-language acquisition. New York: Basic Books.
Birdsong, D. ( 1991). On the notion of "critical period" in UG/L2 theory: A response to Flynn & Manuel. In L. Eubank (Ed.), Pointcounterpoint: Universal Grammar in the second language (pp. 147- 165). Amsterdam: John Benjamins.