title: Critical evidence: a test of the critical-period hypothesis for second-language acquisition.
abstract: The critical-period hypothesis for second-language acquisition was tested on data from the 1990 U.S. Census using responses from 2.3 million immigrants with Spanish or Chinese language backgrounds. The analyses tested a key prediction of the hypothesis, namely, that the line regressing second-language attainment on age of immigration would be markedly different on either side of the critical-age point. Predictions tested were that there would be a difference in slope, a difference in the mean while controlling for slope, or both. The results showed large linear effects for level of education and for age of immigration, but a negligible amount of additional variance was accounted for when the parameters for difference in slope and difference in means were estimated. Thus, the pattern of decline in second-language acquisition failed to produce the discontinuity that is an essential hallmark of a critical period.
authors.affiliation: Stanford University, CA 94305, USA. hakuta@stanford.edu
authors.forename: Kenji
authors.initials: K
authors.lastname: Hakuta
authors.forename: Ellen
authors.initials: E
authors.lastname: Bialystok
authors.forename: Edward
authors.initials: E
authors.lastname: Wiley
mesh_terms: D000367:Age Factors; D004522:Educational Status; D004641:Emigration and Immigration; D006801:Humans; D007802:Language; D014706:Verbal Learning