Effort and coordination in the production of bilabial consonants

The first goal of this study was to compare two methods of measurement of lip articulation force. Bilabial consonants (/p/, /b/, /m/) were produced by a single French female speaker in modal and whispered speech, with varying levels of vocal effort. Lip compression force measured with a pressure sensor glued on the lower lip, correlates significantly, though only partially, with lip muscle activity, measured with surface EMG. The second goal was to better understand the variations of lip articulation force in the production of stop consonant. Variations in lip compression correlate significantly, but not with a high level of correlation, with the variations in intra-oral pressure. This does not support the idea that the primary goal of lip compression is to oppose to the pressure built up in the oral cavity. Lip compression force and Pio were found to correlate significantly, though moderately, with the intensity of the burst created at occlusion release, but not with its spectrum mean