Interaction of jaw displacement and F0 peak in syllables produced with contrastive emphasis

In order to explore the articulatory nature of contrastive emphasis, this study compares contrastively emphasized and non-emphasized syllables in terms of mandible position and F0 peaks. The stimuli were English mono-syllabic words with /aI/, spoken in short utterances as part of read dialogues. Articulatory and acoustic data obtained by the University of Wisconsin x-ray microbeam facilities from six American English speakers were analyzed. The results show that for emphasized syllables, the jaw is lower and generally more front, and F0 is higher, compared to non-emphasized syllables. In addition to corroborating previous observations about larger jaw opening and higher F0 for emphasized syllables, our new finding is protrusion of the jaw in emphasized syllables. A possible hypothesis that we entertain in this paper is that fronting of the jaw may allow large jaw opening with high F0 target. We offer a tentative, yet concrete, hypothesis about the biomechanical interaction between F0 control and jaw opening mediated by anatomical connections between the jaw and the larynx.