The goal of much of the psycholinguistic work on sentence processing has been to identify the sources of information that listeners/readers use to make first-pass 'parsing' decisions and to specify the time course at which they use these sources. Some theories argue that the parser only has access to syntactic information initially, while other accounts claim that the parser has immediate access to multiple sources of information, such as plausibility/thematic fit, which can reduce the likelihood that listeners/readers will construct an erroneous first-pass parse. Interestingly, this work has largely ignored a major property of language that is processed in the auditory modality — prosodic information. In principle, prosodic information could cue and bias listeners towards a certain syntactic parse before they actively make a parsing decision. As such, any comprehensive model of auditory language processing would be well-advised to address the role of prosody. This dissertation approached this issue from two different but complementary perspectives. First, prosody was examined from the position of the speaker and then, from the position of the listener. Study 1 explored how speakers produced prosody at the lexical level by unconsciously biasing them to produce a particular interpretation of an ambiguous idiomatic phrase embedded in a sentence. Acoustic analyses revealed that speakers produced distinct acoustic cues to differentiate between the two possible meanings. Study 2 examined if these acoustic differences could be reflected at even lower-levels of the speech production system, such as the kinematic/motor speech level. Kinematic analyses also showed that speakers moved their articulators differently to distinguish between the two interpretations of an ambiguous idiomatic phrase. Study 3 used pupillometry to investigate the role of prosody in on-line sentence processing, particularly when pitted against thematic fit information. Results indicated that prosody drives first-pass parsing decisions more strongly than plausibility. This dissertation demonstrates that prosody as an important source of information both in production and comprehension. Speakers produce acoustic cues that coincide with the intent of their utterances and move their articulators differently in conjunction with these cues, and listeners exploit these cues in real time to assist in rapid sentence processing and comprehension.