Language users’ expectations shape phonetic flexibility

Language users show considerable flexibility in their phonetic perception and production. Phonetic flexibility phenomena such as convergence and perceptual learning are of broad interest because of their connections to questions in language learning, sociolinguistic variation, and diachronic change. In this talk I will present two case studies on how phonetic flexibility is influenced by language users’ expectations. The first case study is on expectation-driven convergence, which is when speakers converge toward a regional accent feature that they expect, but crucially do not hear, from an interlocutor. In work with Lacey Wade and Dave Embick, we show that people with different dialect backgrounds exhibit expectation-driven convergence triggered by different kinds of sociolinguistic expectations. The second case study is on cross-talker generalization in perceptual learning, which is when listeners shift a perceptual category boundary based on input from one talker and then, under some circumstances, extend that expectation to a different talker. In work with Wei Lai, we propose that perceptual learning involves learning both a bias toward identifying a particular phonological category and a new phonetic boundary between two phonemes, and that listeners will generalize the shift only when those two aspects of what they have learned match. I conclude with reflections on the thematic parallels between these two case studies and potential implications for understanding larger-scale phenomena like language change.