Department of Special Education and Communication Disorders


Date of this Version



Published in Journal of Communication Disorders 42:4 (July-August 2009), pp. 286–298; ASHA 2008 Research Symposium: Neurobiological Determinants of Human Communication: Prematurity and Early Childhood; doi: 10.1016/j.jcomdis.2009.03.008 Copyright © 2009 Elsevier Inc. Used by permission.


This longitudinal investigation examines developmental changes in orofacial movements occurring during the early stages of communication development. The goals were to identify developmental trends in early speech motor performance and to determine how these trends differ across orofacial behaviors thought to vary in cognitive and linguistic demands (i.e., silent spontaneous movements, babble, and first words). Movements of the lower lip and jaw were recorded using a three-dimensional motion capture system. Twenty-four infants were observed every 3 months, from 9 to 21 months of age. Jaw and lower lip speed, and lower lip range of movement increased with age. Silent spontaneous movements were consistently slower than words, whereas kinematic measures associated with babble did not differ from those associated with words. These findings suggest that speech movements may reflect linguistic and cognitive processing demands and that the continuity hypothesis between babbling and words may also be observed at the kinematic level.