Lip kinematics in long and short stop and fricative consonants

Abstract

This paper examines lip and jaw kinematics in the production of labial stop and fricative consonants where the duration of the oral closure/constriction is varied for linguistic purposes. The subjects were speakers of Japanese and Swedish, two languages that have a contrast between short and long consonants. Lip and jaw movements were recorded using a magnetometer system. Based on earlier work showing that the lips are moving at a high velocity at the oral closure, it was hypothesized that speakers could control closure/constriction duration by varying the position of a virtual target for the lips. According to this hypothesis, the peak vertical position of the lower lip during the oral closure/constriction should be higher for the long than for the short consonants. This would result in the lips staying in contact for a longer period. The results show that this is the case for the Japanese subjects and one Swedish subject who produced non-overlapping distributions of closure/ constriction duration for the two categories. However, the peak velocity of the lower lip raising movement did not differ between the two categories. Thus if the lip movements in speech are controlled by specifying a virtual target, that control must involve variations in both the position and the timing of the target.

FIG. 1

A short (left panel) and a long (right panel) nasal consonant produced by Japanese subject NY. The shaded area in each panel shows the oral closure for the consonant. The arrows point at the peak velocities of the upper and lower lip closing movements.

FIG. 2

Closure duration (mean and standard deviation) for the Swedish subjects.

FIG. 3

Closure duration (mean and standard deviation) for the Japanese subjects.

FIG. 4

Average lip and jaw signals for the Japanese subjects HI and MY. The arrows show the direction of movement. The subjects are facing to the left. Average lip and jaw signals for the Japanese subjects NY and SS. The arrows show the direction of movement. The subjects are facing to the left.

FIG. 4

Average lip and jaw signals for the Japanese subjects HI and MY. The arrows show the direction of movement. The subjects are facing to the left. Average lip and jaw signals for the Japanese subjects NY and SS. The arrows show the direction of movement. The subjects are facing to the left.

FIG. 5

Peak upper lip lowering velocity for the Swedish and Japanese subjects (mean and standard deviation).

FIG. 6

Peak lower lip vertical position (mean and standard deviation) for the Swedish subjects.

FIG. 7

Peak lower lip vertical position (mean and standard deviation) for the Japanese subjects.

FIG. 8

Peak velocity of the lower lip closing movement (mean and standard deviation) for the Japanese subjects.

FIG. 9

Lower lip raising displacement and peak velocity for the Japanese subjects’ production of labial stops. Lower lip raising displacement and peak velocity for the Japanese subjects’ production of labial nasals.

FIG. 9

Lower lip raising displacement and peak velocity for the Japanese subjects’ production of labial stops. Lower lip raising displacement and peak velocity for the Japanese subjects’ production of labial nasals.

FIG. 10

Signal averages of lower lip position, velocity, and acceleration for the labial stops produced by the Japanese subjects HI and MY. The vertical line in the velocity and acceleration panels represents zero velocity and acceleration. Signal averages of lower lip position, velocity, and acceleration for the labial stops produced by the Japanese subjects NY and SS. The vertical line in the velocity and acceleration panels represents zero velocity and acceleration.

FIG. 10

Signal averages of lower lip position, velocity, and acceleration for the labial stops produced by the Japanese subjects HI and MY. The vertical line in the velocity and acceleration panels represents zero velocity and acceleration. Signal averages of lower lip position, velocity, and acceleration for the labial stops produced by the Japanese subjects NY and SS. The vertical line in the velocity and acceleration panels represents zero velocity and acceleration.

FIG. 11

Signal averages of lower lip position, velocity, and acceleration for the labial nasals produced by the Japanese subjects HI and MY. The vertical line in the velocity and acceleration panels represents zero velocity and acceleration. Signal averages of lower lip position, velocity, and acceleration for the labial nasals produced by the Japanese subjects NY and SS. The vertical line in the velocity and acceleration panels represents zero velocity and acceleration.

FIG. 11

Signal averages of lower lip position, velocity, and acceleration for the labial nasals produced by the Japanese subjects HI and MY. The vertical line in the velocity and acceleration panels represents zero velocity and acceleration. Signal averages of lower lip position, velocity, and acceleration for the labial nasals produced by the Japanese subjects NY and SS. The vertical line in the velocity and acceleration panels represents zero velocity and acceleration.

FIG. 12

The interval from movement onset to peak velocity (mean and standard deviation) of the lower lip closing movement for the Japanese subjects. The interval from movement onset to peak velocity (mean and standard deviation) of the lip aperture closing movement for the Japanese subjects.