Effects of vowel devoicing on the closure duration of japanese singleton and geminate stops

Abstract

Closure duration is an acoustic variable known to distinguish Japanese singleton and geminate stops. It has been established that the closure duration varies with speaking rate. However, it has not been determined whether the closure duration is affected by devoicing of vowels preceding or following the stops. To determine the effects of such vowel devoicing, a production experiment was conducted with 20 Japanese native speakers. They pronounced four minimal pairs of onomatopoeic words contrasting singleton and geminate stops at various speaking rates. Devoiced vowels were found to affect closure duration preceding the stops, such that the closure with a devoiced preceding vowel is longer than that with a voiced preceding vowel, although the effect is weak for singleton stops. However, devoiced vowels do not affect the duration when they follow stops. These results suggest that vowel devoicing interacts with an acoustic variable of stop consonants, especially in the case of geminate stop.