Determinants of Lengths of Repetition Disfluencies: Probabilistic syntactic constituency in speech production

1 Introduction Usage-based theories of grammar suggest that constituent structure emerges in part from co-occurrence: items used together fuse together forming cohesive, hard-to-interrupt units (Bybee 2002, see also Gregory et al. 1999, Kapatsinski 2010, Stefanowitsch & Gries 2003). This study is an effort to investigate the effects of co-occurrence on constituent structure in language production. We investigate these effects by looking at repetition disfluencies, in which one or more elements in the sentence are repeated after an interruption point in speech. Repetition disfluencies have been argued to be sensititive to constituency: the speaker restarts production from the major constituent boundary nearest to the point at which the flow of speech was interrupted (the " interruption point " , Clark from the more general hypothesis that the more cohesive a unit, the less likely it is to be interrupted (Kapatsinski 2010). For example, speech production is never restarted from the middle of a word. Given the proposed influence of constituency on repair, we suspected that probabilistic influences on constituency may also affect repetition repair, by making syntactic constituent boundaries located between frequently co-occurring words weaker and thus making the speaker less likely to restart production from those weakened boundaries.