15th International Congress of Phonetic Sciences (ICPhS-15)
This study examines the temporal variations of Japanese long and short vowels due to differences in accentual conditions, speaking rates and syllable positions by analyzing a large-scale database called the "Corpus of Spontaneous Japanese" or CSJ. Analysis revealed a phrase-final lengthening as well as weak but significant effects of accent conditions for long/short vowels and bi-/mono-moraic syllables. Speaking rates consistently influenced temporal features, however these effects were more pronounced in the long vowels than in the short ones, resulting in shortening of the long to short vowel ratios due to an increment of speaking rate. These differences were only significant between the slowest category, Category 1 and the rest of the categories, which means that Japanese durational contrast remained constant in normal, fast and very fast speaking rates, even in spontaneous speech.
Bibliographic reference. Minagawa, Yasuyo / Kagomiya, Takayuki / Maekawa, Kikuo (2003): "Durational variations of Japanese long/short vowels in different speaking rates: analysis of a spontaneous speech corpus", In ICPhS-15, 2127-2130.