An exploratory study into the intentionality of disfluency production

Abstract

Much research has been conducted into the ways that listeners make use of disfluencies in a speech stream. Conversely, there has been very little work conducted on the production of disfluencies. One particularly under researched question is whether disfluencies are an epiphenomenon of speech production problems (e.g. Oomen & Postma, 2001) or if they are used intentionally to signal upcoming delays or to comment on some facet of the speech stream (e.g. Clark & Fox Tree, 2002). Additionally, there has been suggestion that disfluencies do not act as a homogeneous group and might perform different functions within an utterance (e.g. Bortfeld et al. 2001). We perform an exploratory study which begins to investigate these claims by manipulating both Performance (epiphenomenon) and Competence (intentional usage) related factors within a controlled experimental environment. The results of this experiment are indexed by disfluency type to allow between type comparisons. Twenty Four participants undertook the experiment and produced a total of 1344 spontaneously generated but roughly formulaic utterances for analysis. Our main finding that Performance factors can increase the usage of certain types of disfluency (a) expands on previous findings that Performance factors can be manipulated experimentally, and (b) suggests that disfluencies should be treated individually rather than as a homogenous group. We find little support for the intentional use of any form of disfluency within this experiment.