Effects of Laryngeal Activity on Articulation

This study examined the effects of three speech conditions (voiced, whispered, and mouthed) on global average measures of articulatory movement during sentence production. Participants were 20 adults (ten males and ten females) with no history of speech, language, or hearing disorders. They produced six target utterances in the three speaking conditions. Movements of the following articulators were recorded with an electromagnetic articulograph: Mid tongue, front of tongue, jaw, lower lip, and upper lip. The kinematic metrics were averages derived from movement strokes defined by minima in the speed record of each articulator. These measures revealed a number of significant changes between the voiced and mouthed conditions, with relatively few differences between voiced and whispered speech. Significant increases in sentence duration, articulatory stroke count, and stroke duration as well as significant decreases in peak stroke speed, stroke distance, and hull areas were found in the mouthed condition. These findings suggest that both laryngeal activation and auditory feedback play an important role in the production of normally articulated vocal tract movements, and that the absence of these may account for the significant changes in articulation between the voiced and mouthed conditions.