Syntactic and Prosodic Phrasal Alignment in Naturalistic Language.

Prosody is an intrinsic element of language production, linking together multiple levels of linguistic representation to shape both the structure and interpretation of utterances. However, common theories of prosodic phrasing in spoken language often fail to capture factors associated with planning and recovery, as well as performance-based effects related to working memory. Much of what we know about prosody, whether it be the features speakers are thought to generate or the ones listeners are believed to process, is based on forms that are atypical in spoken language. Recent developments in data analysis methods, however, allow for the efficient study of unrehearsed spoken language. The current work aims to develop more ecologically valid theories of prosody and its relationship to syntactic structure through the analysis of unrehearsed scene descriptions. Data from unrehearsed speech collected across four different studies showed only a weak to moderate relationship between prosodic phrasing and syntactic structure, such that the likelihood of a prosodic phrase boundary occurring at the end of a syntactic phrase was only slightly above chance. Additionally, correlations between occurrences of prosodic phrase boundaries and speech rate revealed that individuals who speak more slowly are likely to insert more prosodic phrase boundaries, indicating a relationship between prosodic phrasing and speech planning. The findings challenge some categorical approaches to prosody and suggest that prosodic phrasing may be a consequence of planning and recovery in language production, rather than a complement to syntactic phrasing. These results have implications for theories of language production and comprehension, formal theories of phonological structure, and computational tools for generating and interpreting language.