Exemplar Dynamics in Phonetic Convergence of Speech Rate

We motivate and test an exemplar-theoretic view of phonetic convergence, in which convergence effects arise because exemplars just perceived in a conversation are stored in a speaker’s memory, and used subsequently in speech production. Most exemplar models assume that production targets are established using stored exemplars, taking into account their frequencyand recency-influenced level of activation. Thus, convergence effects are expected to arise because the exemplars just perceived from a partner have a comparably high activation. However, in the case of frequent exemplars, this effect should be countered by the high frequency of already stored, older exemplars. We test this assumption by examining speech rate convergence in spontaneous speech by female German speakers. We fit two linear mixed models, calculating speech rate on the basis of either infrequent, or frequent, syllables, and predict a speaker’s speech rate in a phrase by the partner’s speech rate in the preceding phrase. As anticipated, we find a significant main effect indicating convergence only for the infrequent syllables. We also find an unexpected significant interaction of the partner’s speech rate and the speaker’s assessment of the partner in terms of likeability, indicating divergence, but again, only for the infrequent case.