Variations in jaw and tongue gestures observed during the production of unstressed /d/s and flaps

Three experiments measured tongue position (electropalatography) and jaw movements (strain gauge) during the production of nonsense phrases composed of repetitions of the syllable “da”. In experiment 1, jaw acceleration was found to vary with allophonic variation rather than with stress level. Experiment 2 found that four acoustic patterns corresponded to several jaw displacement and acceleration patterns. Experiment 3 examined the relationship between tongue palate contact, jaw movement and the acoustic wave. The pattern of tongue-palate contact was related to jaw movement and strongly related to acoustic pattern. Listeners judged specific acoustic patterns to be roughly associated with the production of the phonemes /d/, flap and tap. An additional allophone of /d/, a short /d/ was often utilized for unstressed syllables during rapid speech. This allophone was not perceptually distinguished from the normally long /d/.