A Synthesis of Research on Critical Period for the Accessibility of Universal Grammar and Its Implications

The purpose of this paper is to examine the Critical Period Hypothesis (CPH) in terms of the accessibility of Universal Grammar (UG). If this underlying cognitive system is still available as people grow older, adult learners should be able to attain native levels of L2 proficiency. If, however, the cognitive system becomes inaccessible, adult learners may have difficulty in mastering L2s, further supporting the CPH for L2 acquisition. Before examining this issue, previous research on the CPH was reviewed and synthesized, as was the relationship between UG and language acquisition. Empirical studies were then presented. By delving into these issues, it is hoped that this paper sheds new light on the CPH and provides educators with an improved understanding of L2 teaching and learning.