Effects of Language Predictability and Speech Rate on Speech Entrainment Performance in Healthy Individuals

Speech entrainment, a paradigm in which a participant shadows the speech of an audiovisual model in real time, has been show to benefit individuals with non-fluent aphasia. A study examining the effects of language predictability and speech rate was conducted to understand factors that influence speech entrainment performance. A recent study by Fridriksson and colleagues (2012) demonstrated that training with speech entrainment significantly increased the number of words participants with non-fluent aphasia were able to produce. Perhaps even more remarkably, these effects showed generalization. As a result, speech entrainment could be used to rehabilitate speech impairment in stroke. However, there is very limited understanding of the factors that drive and influence speech entrainment performance. In order to better understand the implications of speech entrainment as a therapeutic technique, the current study examines some of the factors we predict may influence speech entrainment performance. This performance will be measured by comparing the delay (in time) between an audiovisual model and the speech of the healthy participants during a speech entrainment task at specific points in a sentence. Forty participants were recruited from the study body at the University of South Carolina. During the study, normal participants completed either: 1) a speech rate experiment: an experimental paradigm that manipulates the rate of the audiovisual presentation or 2) a language predictability experiment: an experimental paradigm that manipulates the predictability of upcoming words in a sentence. Twenty participants completed the language predictability task, and twenty participants completed the speech rate task. Error analysis, effects of cloze probability, and speech entrainment accuracy were also explored