Retesting the Critical Period Hypothesis - Is Age a Strong Predictor of Ultimate Attainment in SLA?

Retesting the Critical Period Hypothesis

  The major purpose of this study was to test the critical period hypothesis for the acquisition of English articles. The participants were 82 native speakers of Korean who differed according to the age of arrival (AOA) in the United States (2 to 43 years), but were all fully exposed to English (mean length of residence=18 years). The participants" knowledge of English articles was assessed using a 102-item article cloze test. As AOA increased, the article test scores decreased steadily. However, the effect of AOA on the article test scores became nonsignificant when variables confounded with AOA-the participants" age, years of education in the United States, use of English-were controlled. The finding suggests that the observed age difference in the article scores did not result from passing a maturationally defined critical period. Another purpose of this study was to examine the predictive power of AOA when it is considered with other predictors of the article test scores. A stepwise multiple regression analysis showed that the participants" use of English (how much the participants use English daily), not AOA (when the participants began to be extensively exposed in English), was the most powerful predictor of the article test scores. All of the findings of the study indicated that a careful attention should be paid on other variables confounded with AOA and outcome when investigating the critical period hypothesis.