Experience effects on the development of late second language learners’ oral proficiency

摘要

The aim of this study is to evaluate the effects of language experience—operationalized as length of residence—on late second language learners. Data collected from 65 participants consists of three groups of Japanese learners of English (n = 13 Short-, Mid-, Long-LOR Groups, respectively) and two groups of baseline speakers (n = 13 for inexperienced Japanese speakers and native English speakers, respectively). The global quality of their spontaneous speech production was initially judged by 10 native speaking raters of English based on accentedness (linguistic nativelikeness) and comprehensibility (ease of understanding), and then submitted to segmental, prosodic, temporal, lexical, and grammatical analyses. According to the results, LOR was generally predictive of improved L2 comprehensibility as a result of the continuous development of good prosody, optimal speech rate, and proper lexicogrammar usage, while a great amount of L2 experience was required to enhance accentedness, which entailed refined segmental accuracy, vocabulary richness, and grammatical complexity. These results, in turn, suggest L2 learners continue to improve L2 oral proficiency over an extensive period of L2 immersion (e.g., 6 years of LOR), and they do so by paying selective attention to certain linguistic domains closely linked to comprehensibility—but not necessarily relevant to accentedness—for the purpose of successful L2 communication.