摘要：The idea of "earlier is better" is modified by the concept of a "Critical Period" in a person's age during which language acquisition is optimal. It is controversial when applied to L2 acquisition (L2A). Evidence from a close examination of the studies relating age to L2A supports the proposition that there is a period in the learner's age when L2 is acquired more proficiently in terms of the final language outcome or output. After the "Critical Period", there is a statistical decline in the L2 acquisition by older people. This literature survey is intended to suggest that the age effect is a dominant pervasive influence in L2A and can be interpreted beyond the recognition of a "Critical Period", and, along with other variables in age difference such as the nature of the input and the time committed to learning being taken into consideration. The consideration of age should be reflected in the teaching approaches to different age groups.
