How meaning and predictability affect the duration of Japanese homophonous words

Although a number of studies have challenged the traditional assumption that there are truly homophonous words, they are exclusively based on English, a language in which duration is not phonemic. This study extends research on the phonetic properties of homophonous words to Japanese, a language in which duration is phonemic. Based on a corpus of spontaneous Japanese speech, we found that 1) homophonous words differed in duration among the members of the homophonous group, 2) durations of homophonous words were positively correlated with degrees of certainty about the predicted word forms predicted from the word meanings, and 3) mora duration was sensitive to the contextual predictability of the mora within the word, while word duration was not sensitive to its contextual predictability.