Durational effects of syllable structure and distinctive length in Japanese

The results of a study of Japanese segment durations are reported in which segment identity was tightly controlled in order to reduce the effects of intrinsic segment duration, and distinctive vowel, while consonant length and syllable structure were varied. The corpus includes words with superheavy syllables, consisting of a long vowel followed by a geminate consonant, which have not previously been studied. One surprising result is the interaction observed when the durations of the components of superheavy syllables are compared to those of cognate bimoraic syllables containing a short vowel followed by a geminate consonant. The phonological lengthening of the vowel not only increases vowel duration as expected but also causes a substantial increase (25%–33% depending on the condition) in the duration of the already long consonant. In contrast, comparison of superheavy syllables with bimoraic syllables containing a long vowel followed by a nongeminate consonant showed no consistent effect of the phonological lengthening of the consonant on the duration of the vowel. This also shows that, while the mora count may determine the total duration of the word, the increment in duration due to the addition of a mora is not realized entirely in the segment(s) which that mora contains.