Communicative context, expectations, and adaptation in prosodic production and comprehension

It is generally assumed that prosodic cues that provide linguistic information are driven primarily by the linguistic content of an utterance. However, research has shown that information from different levels of language often interact and affect the production and comprehension of an utterance (e.g., Brown-Schmidt, 2009; Remez, 1981; Ganong, 1980). If prosody operates in a similar manner to other levels of language, speakers and listeners should be sensitive to things such as communicative context, sentence structure, and listener expectations. This paper explores this possibility through a variety of studies. Part 1 investigates whether speakers have the capacity to adjust subtle acoustic-phonetic properties of the prosodic signal when they find themselves in contexts in which accurate communication is important. Thus, we examine whether the communicative context, in addition to discourse structure, modulates prosodic choices when speakers produce acoustic prominence. We manipulated the discourse status of target words in the context of a highly communicative task (i.e., working with a partner to solve puzzles in the computer game Minecraft), and in the context of a less communicative task more typical of psycholinguistic experiments (i.e., picture description). Speakers in the more communicative task produced prosodic cues to discourse structure that were more discriminable than those in the less communicative task. In a second experiment, we found that the presence or absence of a conversational partner drove some, but not all, of these effects. Together, these results suggest that speakers can modulate the prosodic signal in response to the communicative and social context. Part 2 investigates whether listener expectations influence the processing of intonational boundaries. In a boundary detection task, we manipulated a) the strength of cues to the presence of a boundary and b) whether or not a location in the sentence was a plausible location for an intonational boundary to occur given the syntactic structure. In Experiment 1, listeners are instructed to report where they heard disfluencies, even though there were no disfluencies present in the recordings. Listeners report hearing disfluencies at the locations that had intonational boundaries, and they are equally likely to report them in licensed and unlicensed locations for boundaries. This suggests that listeners can interpret prosodic cues to boundaries as disfluencies, and that their expectations as to where disfluencies might occur are more flexible than they are for where boundaries might occur. Experiment 2 makes use of a 2 trial version of the boundary detection paradigm to investigate whether listeners who reported hearing boundaries at unlicensed locations in previous studies (Buxó-Lugo & Watson, 2016) had done so because of adaptation to new types of input. The results replicate previous studies, and find no evidence for adaptation having occurred throughout those experiments. Lastly, we propose 2 studies to investigate whether listeners can adapt to new mappings between prosodic and syntactic structure