Prosodic cues for syntactically-motivated junctures

A pilot study was conducted to examine the manner in which Cantonese speakers use prosody to mark syntactic junctures in speech production. Test sentences were designed to create the intended experimental conditions — each sentence-pair consists of an identical array of morphemes with exactly two interpretations according to two different syntactic structures. These structures can be clarified by conveying prosodic boundaries that coincide with junctures between major syntactic constituents. The purpose of the experiment as well as the meaning of the test sentences (with respect to their syntactic structures) were explained to the subjects. After a few practice runs, they were asked to read these sentences aloud, conveying the marked boundaries, while their voices were being recorded. Three prosodic juncture markers: pauses, pitch reset and pre-boundary lengthening were under examination. Results of the acoustic and statistical analyses of the recorded signals indicated that, pauses were the most effective way of marking junctures, followed by pitch reset. Pre-boundary lengthening was found to be infrequent; in the rare cases where it was detected, pre-boundary syllables were only slightly longer than their non-boundary counterparts. Nonetheless, vast individual differences in terms of the amplitudes and frequencies of prosodic juncture markers were observed. The present study provides acoustical data regarding the manner in which Cantonese speakers use prosody in utterance structure clarification, vis-à-vis their specific language experience. In a large-scale experiment, test sentences will be embedded in contextual paragraphs that semantically and prosodically prompt readers to convey the intended prosodic structure. This experiment is underway and is expected to yield more conclusive results.