Age and Proficiency in L2 Attrition: Data from Two Siblings

摘要

This paper investigates whether any difference exists in the degree of second language attrition between two siblings in terms of grammatical complexity, grammatical accuracy, lexical complexity, and lexical productivity based on their storytelling data collected over the period of 31 months. The subjects’ L1 and L2 are Japanese and English, respectively. The siblings (one male, one female) have similar L2 profiles with respect to attained proficiency, including literacy, but differ in age. The ages of returning home were 7;0, an age reported to be more vulnerable to attrition and 10;0, an age reported to be more resistant. The siblings showed similar attrition patterns suggesting that an attained high proficiency level including the acquisition of literacy skills is an important factor in the maintenance of L2. One exception was grammatical accuracy, but the difference surfaced only after the second year, indicating that the period of disuse was differentially affected according to their ages. The younger sibling's data also suggest that maturational factors may play a role in successfully handling grammatical complexity and accuracy simultaneously.