Phrase-final rise-fall intonation and disfluency in Japanese - a preliminary study

In Japanese conversations, rise-fall intonation with vowel lengthening often occurs on the final syllable of a phrase. This phrase-final rise-fall (PFRF) is a new type of intonation first reported in the 1960’s. Researchers consider PFRF intonation a discourse marker which functions to sharpen the phrase boundary and retain the utterance turn, but other phrase-final intonation such as phrase-final lengthening (PFL) can have a similar pattern. PFLs are recognized as a type of disfluent speech with similar characteristics to PFRFs in terms of final-lengthening and having discourse functions. Also from reports about the spontaneity of speech, we assume that PFRFs would have a relation with disfluency, as well as with PFLs. To examine this assumption, this paper attempts to show the co-occurrence relation between PFRF and disfluency in the same utterance. The results show that PFRFs and PFLs have a relation to posterior disfluent units and suggest that both indicate speech planning strategies. Further, this paper speculates that a difference between PFRF and PFL is a difference in the purposes of speech planning: the latter represents ongoing linguistic editing while the former indicates adjusting the utterance according to the interlocutor’s reaction. Disfluencies accordingly occur as effects from processes of speech planning.