In this paper, we focus on weak clause boundaries in Japanese monologs in order to investigate the relationship of the length of constituents following weak boundaries to three acoustic and linguistic features: 1) occurrence rate of fillers, 2) occurrence rate of boundary pitch movements, and 3) degree of lengthening of clause-final morae. We found that all these features were significantly correlated with the length of following constituents. Most importantly, boundary pitch movements had an additional effect that can be distinct from the effect of clause-final lengthening. These results suggest that Japanese speakers have earlier-occurring items that help them deal with cognitive load in speech planning, in addition to fillers and other clause-initial disfluencies.

Index Terms: fillers, boundary pitch movements, clause-final lengthening, Japanese monologs