Contribution of tongue lateral to consonant production

Speaking requires the coordinated movements of individual articulators. Understanding each articulator’s contribution to speech is fundamental not only for understanding how speech is produced, but also for optimizing speech assessment and treatment. Our recent work has studied the individual contributions of tongue tip, tongue blade, tongue body front, tongue body back, upper lip, and lower lip movement to speech sound production by tracking the motion of sensors attached on the midline of tongue and lips. An optimal set of articulators (tongue tip, tongue body back, upper lip, and lower lip) has been found. However, the tongue lateral (side)’s contribution to speech is still poorly understood. We therefore investigated the contribution of the tongue lateral region to consonant production by analyzing the motion of a sensor attached to the side of tongue. Repeated productions of 12 consonants (including the lateral approximant /l/) were collected from six native English speakers. Consonant classification accuracy based on articulatory movement data obtained using a support vector machine was used as an indication of contribution level. The results suggest that sagittal movement of the tongue lateral sensor did not significantly benefit consonant classification, over and above the optimal set. Implications of these findings are discussed.