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 vowel duration and phonemic vowel length contrast by inexperienced late onset learners whose native language is Australian English (L1). The learners ’ Japanese vowels were obtained by longitudinal data collection over a 1.5 year period beginning at the initial stage of L2 learning. In addition, recordings of Australian English vowels (produced by the learners) and Japanese vowels (produced by native Japanese speakers) were also collected. The results show that Australian English learners were able to adjust vowel duration contrast in L2 Japanese by lengthening long vowels to produce ratios of long to short vowels approaching that of native Japanese speakers. However, the change in duration across vowel type was non-uniform with greater difference between the native language and the target language generating relatively greater change in L2 production. Adjustment of duration in L2 vowels typically appeared at the very early stage of learning but there was some variability between individuals in the patterns of achievement