The timing control of geminate and single stop consonants in Japanese: a challenge for nonnative speakers.

The stop closure durations and voice onset time of geminate and single voiceless stops in Japanese were examined with two groups of subjects: native Japanese and fluent Americans. The two groups were found to have different manners of timing control of these segments. The results indicated that the 10 native speakers distinguished between the geminate and single stops by controlling the closure durations in the mean ratio of 2.8:1.0, while the 4 fluent Americans pronounced the same tokens in diverse and random manners. The timing control of geminate and single stop consonants is a challenge for nonnative speakers who may either miss the contrast, or may pronounce geminate and single stops with the ratio of approximately 2.0:1.0.