VOT of stop consonants in a Japanese-English bilingual child

This is a phonetic study of a child who was raised in a Japanese-English bilingual setting. It explores three general questions, focusing on Voice Onset Time. (1) We got the evidence that the child began to distinguish three VOT values for three phonemes in English (/p, t, k/) between the age of 2;6 and 2;8, that is, he began to produce these three phonemes accurately in terms of VOT. (2) It was observed that the child's VOT mean values for English voiceless stops and Japanese velar stops got larger from 2;6 and 2;8, and got smaller from 2;8 to 2;10. That is, it seems that in the process of development; children may over-shoot their targets and then shorten of readujust to attain them. (3) The results that the child's VOT mean values of English /k/ were always higher than Japanese /k/ indicates that the child distinguishes two languages, Japanese and English, even at the age of 2;6.