Margaret Zellers, Research Centre for English and Applied Linguistics, University of Cambridge
Brechtje Post, Research Centre for English and Applied Linguistics, University of Cambridge
Topic structure in longer discourses has been shown to be marked in speech by prosodic variations, e.g. variations in fundamental frequency (F0) and speech rate. We investigated whether variations in voice quality, specifically aperiodicity as an aspect of glottalization, were also signals to topic structure by varying to indicate the strength of discourse boundaries. We found that variation in the presence of aperiodicity and length of aperiodic stretches were not good cues to topic structure; although there was some effect of topic structure on the presence of aperiodicity, the length of the aperiodic stretches did not correlate with topic structure at all. However, it still varied systematically in relation to F0 movements, and as such may be used as a cue to signal other linguistic structure.