Two auditory comprehension studies investigated the role of focus, as conveyed by a pitch accent, in the comprehension of relative clauses preceded by a complex NP (e.g. the propeller of the plane that . . .). In the rst experiment, accenting N 1 (propeller) or N 2 (plane) increased the probability that the accented NP would be taken as head of the relative clause. This supported the predictions of a Focus Attraction Hypothesis as applied to relative clauses. The second experiment manipulated the prosodic status of the relative clause (accented or unaccented) as well as the type of accent on a potential head of the relative clause. It demonstrated that focus on a potential head of a relative clause attracts both accented relative clauses, presumed to convey new information, and unaccented relative clauses, presumed to convey given information. This supported a straightforwa rd version of the Focus Attractio n Hypothesis as opposed to a Congruence Hypothesis, which claims that only modi ers marked as conveying new information preferentially are related to other phrases that are marked as new. The experiment also demonstrated that a contrastive accent on a potential head of a relative clause attracts relative clauses even more than a focal accent that is appropriate for new information.

Two sentence processing experiments on a dative NP ambiguity in Korean demonstrate effects of phrase length on overt and implicit prosody. Both experiments controlled non-prosodic length factors by using long versus short proper names that occurred before the syntactically critical material. Experiment 1 found that long phrases induce different prosodic phrasing than short phrases in a read-aloud task and change the preferred interpretation of globally ambiguous sentences. It also showed that speakers who have been told of the ambiguity can provide significantly different prosody for the two interpretations, for both lengths. Experiment 2 verified that prosodic patterns found in first-pass pronunciations predict self-paced reading patterns for silent reading. The results extend the coverage of the Implicit Prosody Hypothesis [Fodor, J Psycholinguist Res 27:285-319, 1998; Prosodic disambiguation in silent reading. In M. Hirotani (Ed.), NELS 32 (pp. 113-132). Amherst, MA: GLSA Publications, 2002] to another construction and to Korean. They further indicate that strong syntactic biases can have rapid effects on the formulation of implicit prosody.

Speakers' prosodic marking of syntactic constituency is often measured in sentence reading tasks that lack realistic situational constraints on speaking. Results from such studies can be criticized because the pragmatic goals of readers differ dramatically from those of speakers in typical conversation. On the other hand, recordings of unscripted speech do not readily yield the carefully controlled contrasts required for many research purposes. Our research employs a cooperative game task, in which two speakers use utterances from a predetermined set to negotiate moves around gameboards. Results from a set of early versus late closure ambiguities suggest that speakers signal this syntactic difference with prosody even when the utterance context fully disambiguates the structure. Phonetic and phonological analyses show reliable prosodic disambiguation in speakers' productions; results of a comprehension task indicate that listeners can successfully use prosodic cues to categorize syntactically ambiguous fragments as portions of early or late closure utterances.

A series of speech production and categorization experiments demonstrates that naïve speakers and listeners reliably use correspondences between prosodic phrasing and syntactic constituent structure to resolve standing and temporary ambiguity. Materials obtained from a co-operative gameboard task show that prosodic phrasing effects (e.g., the location of the strongest break in an utterance) are independent of discourse factors that might be expected to influence the impact of syntactic ambiguity, including the availability of visual referents for the meanings of ambiguous utterances and the use of utterances as instructions versus confirmations of instructions. These effects hold across two dialects of English, spoken in the American Midwest, and New Zealand. Results from PP-attachment and verb transitivity ambiguities indicate clearly that the production of prosody-syntax correspondences is not conditional upon situational disambiguation of syntactic structure, but is rather more directly tied to grammatical constraints on the production of prosodic and syntactic form. Differences between our results and those reported elsewhere are best explained in terms of differences in task demands.

It has been suggested that prosodic disambiguation of sentences is largely a matter of prosodic phrasing. Ambiguities can be resolved if a prosodic break aligns with a major syntactic boundary of one structure but not another. The placement of pitch accents is viewed as playing only a supporting role (cf. Price, Ostendorf, Shattuck-Huffnagel, & Fong, 1991). This view of prosodic disambiguation does not apply tho all structures of a language. We report five experiments studying ambiguous sentences like (i) and (ii): (i) I asked the pretty little girl WHO is cold. I asked the pretty little girl who is COLD. (ii) Joshua began to wonder WHEN his girlfriend got a tattoo. Joshua began to wonder when his girl friend got a TATTOO. The presence of a prominent pitch accent on the interrogative constituent ( who, when) biased listeners to a emmbedded question interpretation whereas its absence biased thhem to a relative clause(i) or temporal adjunct(ii) analysis. The results suggest that accent, like prosodic breaks, can play a central role in guiding sentence comprehension.