Development of Japanese length contrast: a longitudinal study of L2 vowels produced by Australian learners of Japanese

In this study we investigate the acquisition of Japanese phonemic vowel length contrast by learners whose native language is Australian English (L1). The learners' Japanese vowels were obtained by longitudinal data collection over a 2 year period beginning at the initial stage of L2 learning. In order to examine L2 achievement, an analysis of vowel durational characteristics of Australian English and Japanese (produced by native Japanese speakers) was also conducted. Australian English learners of Japanese were able to achieve vowel duration contrast in L2 Japanese by lengthening long vowels to produce ratios of long to short vowels approaching that of native Japanese speakers. The results show that the degree of difference between the two languages predicts L1-L2 change. Length adjustments across vowel type were non-uniform with greater difference between the native language and the target language generating relatively greater change in L2 production. Previous studies have suggested that features with high functional load in L1 will be easily applied to L2 and those with a lower functional load will be less effectively applied (McAllister et al., 2001). In this study we examine the variable functional load of Australian English vowel duration and its relationship to achievement of Japanese phonemic vowel contrast.