Synthesizing meaning and processing approaches to prosody: performance matters.

Words vary in acoustic prominence; for example repeated words tend to be reduced, while focused elements tend to be acoustically prominent. We discuss two approaches to this phenomenon. On the message-based view, acoustic choices signal the speaker's meaning or pragmatics, or are guided by syntactic structure. On the facilitation-based view, reduced forms reflect facilitation of production processing mechanisms. We argue that message-based constraints correlate systematically with production facilitation. Moreover, we argue that discourse effects on acoustic reduction may be at least partially mediated by processing facilitation. Thus, research needs to simultaneously consider both competence (message) and performance (processing) constraints on prosody, specifically in terms of the psychological mechanisms underlying acoustic reduction. To facilitate this goal, we present preliminary processing models of message-based and facilitation-based approaches, and outline directions for future research.