What Factors are Predictors of Successful

This study investigates the effects of age of onset (AO) along with length of stay (LS) on the proficiency of English as a second language. Subjects include 48 Japanese high school students who had lived in the United States for more than two years (M = 5.79 years) and received formal instructions in English at local schools. The dependent variables, English pronunciation in terms of the degree of foreign accent (FA) and attainment in syntax, lexis, and morphological as measured by TOEFL scores, were examined to find correlations with the independent variables AO and LS. Subjects ' FA highly correlates with their AO (.4988), but TOEFL scores failed to correlate with AO (-.2760). LS negatively correlates with FA (-.4826) but positively correlates with TOEFL (.4135). Observed FA is decreased with the younger AO but LS is found to better predict overall attainment of English as a second language. Critical period for second language acquisition, in the case of phonology, seems to exist, but not overtly observed for other domains of the target language in this study