Articulatory Kinematics in the Control of Closure/Constriction Duration in Speech
This study examined the control of closure/constriction duration of labial and lingual consonants using records of articulatory kinematics. Nativer speakers of Japanese served as subjects. Based on earlier work on lip and tongue kinematics in speech, a number of specific hypotheses for the labial and lingual consonants were evaluated. For the labial consonants, the lower lip reached a higher vertical position for the long than the short stops, and the magnitude of the lower lip closing movement was larger for the long stops. The peak velocity of the lower lip closing movement did not differ between consonant categories. An analysis of the lower lip closing velocity and acceleration indicated that they differed for the long and short consonants. In particular, the lower lip reached its highest vertical position later during the closure for the long than for the short consonants. Thus, the simple idea of only a change in the position of a virtual target for the lower lip is not correct. Its timing also has to change. For the lingual consonants, there was no difference in the magnitude of the tongue movement during the closure/constriction between long and short consonants, but its average speed was lower fof the long consonants.