Vowel reduction: A usage-based perspective

From a usage-based perspective, reduction results from automatization of stored gesture sequences corresponding to words and phrases, which accompanies reuse. In this paper, we discuss the mechanisms of and constraints on automatization, and examine its consequences for vocalic gestures in prosodically weak positions in a typologically and genetically diverse language sample. We show that vowels shorten, devoice, unround, and centralize (with some raising). These kinds of reductions are late-acquired speech patterns which represent highly skilled behavior that results from extensive practice. Reduction is also intricately conditioned by the discourse context. We argue that the leaders of reductive change are adults, who know when and how to reduce in ways sanctioned by the speech community, and have the social cachet to influence other speakers. Reductive change is not due to imperfections in intergenerational transmission. Rather, it is the outcome of lifelong optimization of goal-directed movement patterns constrained by feedback from interlocutors.