Limited effects of early language learning on second language speech production.

Knightly et al. (2003) report long-term production benefits of childhood second language (L2) exposure in a naturalistic setting. However, it is unknown whether or not their finding will apply to classroom L2 learning. This study compares the production of voice onset time (VOT) in English and Japanese and closure duration of singletons and geminates in Japanese by English-speaking university students (n=15) who graduated from a Japanese immersion program (early learners) and adult learners of Japanese (n=15) with no exposure to Japanese in childhood (late learners). The informants were asked to repeat several target words including initial /p, t, k/ for VOT, and medial /p, t, k/ and /pp, tt, kk/ for singletons and geminates in a sentence frame. Both VOT of the initial stops and closure duration of the medial stops were measured. The results show that the production of VOT and closure duration by the early learners was not significantly different from that of the late learners (p=0.71 and p=0.13, respectively). The findings may hypothesize that there are only limited effects of classroom L2 exposure in childhood on L2 speech production in adulthood. [Work supported by Grant-in-Aid for Scientific Research (C) 20520527.]