MECHANICAL PERTURBATION OF JAW MOVEMENTS DURING SPEECH - EFFECTS ON ARTICULATION AND PHONATION

12 subjects uttered the testword /papapas/ repeatedly with three diffe rent speech rates and two stress patterns. On 17% randomly chosen tria ls, a mechanical load was applied unpredictably to the jaw in the dire ction of the opening movement. Load onset was triggered by the start o f the first phonation. Analysis showed that the opening and dosing dis placements of the jaw movement in the first syllable were not influenc ed significantly by the perturbation. The load application prolonged t he duration of the jaw movement in unstressed syllables but not in str essed syllables. Further, the mechanical perturbation of the jaw led t o increased duration of phonation in unstressed syllables only, the ef fect for duration of phonation being greater at higher speech rates. T hese results demonstrate a coupling between articulation and phonation .