2Bialystok E.The structure of age: in search of barriers to second language acquisition. Second Language Research . 1997
3Lenneberg EH.Biological Foundations of Language. Journal of Women s Health . 1967
4Johnson JS,Newport EL.Critical period effects in second language learning: the influence of maturational state on the acquisition of English as a second language. Cognitive Psychology . 1989
5Hakuta K.A critical period for second language acquisition?A status review[].wwwstandfordedu/-hakuta/Docs/CriticalPeriodPDF.
6Flege J E.Speech learning in a second language[].Phonological Development:ModelsResearchImplications.1992
5Birdsong, D. Second Language Acquisition and the Critical Period Hypothesis[M]. Mahwah, NJ: Lawrence Erlbaum Associates, 1999.
6Gould J L & Marler P. Learning by Instinct[J]. Scientific American. 1987. (256).
7Hatch, E. Psycholinguistics: Second Language Perspective[M]. Rowley Mass: Newbury House. 1983.
8Krashen S et al. (eds.) Cold- adult Difference in Second Language Acquisition[M]. Rowley Mass: Newbury House. 1982.
9Littlewood, W. Foreign and Second Language Learning[M]. Cambridge University Press. 1984.
10Singleton, D. Introduction: A Critical Look at the Critical Period Hypothesis in Second Language Acquisition Research. In Singleton, D & Lengyel Z. (eds.): The Age Factor in Second Language Acquisition[M] . Clevedon. 1995.
