The Role of Prosody in Disambiguating English Indirect Requests.

Ambiguity pervades language. The sentence "My office is really hot" could be interpreted as a complaint about the temperature or as an indirect request to turn on the air conditioning. How do comprehenders determine a speaker's intended interpretation? One possibility is that speakers and comprehenders exploit prosody to overcome the pragmatic ambiguity inherent in indirect requests. In a pre-registered behavioral experiment, we find that human listeners can successfully determine whether a given utterance was intended as a request at a rate above chance (55%), above and beyond the prior probability of a given sentence being interpreted as a request. Moreover, we find that a classifier equipped with seven acoustic features can detect the original intent of an utterance with 65% accuracy. Finally, consistent with past work, the duration, pitch, and pitch slope of an utterance emerge both as significant correlates of a speaker's original intent and as predictors of comprehenders' pragmatic interpretation. These results suggest that human and machine comprehenders alike can use prosody to enrich the meaning of ambiguous utterances, such as indirect requests.