Bayesian Speech Production: Evidence from Latency and Hyperarticulation

Both response latency and phonetic variation reflect competition among alternatives during the speech production process. A review of the literature finds an apparent contradiction in the latency results. In some tasks where latency is measured, similarity between targets and competitors results in slower reaction times. In other tasks, similar competitors appear to facilitate production times relative to non-similar competitors (though a lack of any competition at all results in the shortest response latencies). With respect to phonetic realization, experiments suggest that high levels of competition induced by sufficiently similar competitors result in hyperarticulation of target utterances. We present a Bayesian model of speech production that formalizes the selection and planning of spoken forms as noisy-channel communication among different levels of processing. The model resolves the apparent contradiction found in the latency results, and establishes a novel connection between those results and observed patterns of hyperarticulation.