The co-emergence of cognition, language, and speech motor control in early development: a longitudinal correlation study.

UNLABELLED: Although the development of spoken language is dependent on the emergence of cognitive, language, and speech motor skills, knowledge about how these domains interact during the early stages of communication development is currently limited. This exploratory investigation examines the strength of associations between longitudinal changes in articulatory kinematics and development of skills in multiple domains thought to support early communication development. Twenty-four children were investigated every 3 months between the ages of 9 and 21 months. Movements of the upper lip, lower lip, and jaw were transduced using a three-dimensional motion capture system to obtain age-related changes in movement speed and range of movement. Standardized measures of cognition and language from the Battelle Developmental Inventory, 2nd edition and the MacArthur-Bates Communicative Development Inventory were also collected. Significant associations were identified between orofacial kinematic and the standardized measures of language and cognitive skills, even when age served as covariate. These findings provide preliminary evidence of interactions between cognition, language, and speech motor skills during early communication development. Further work is needed to identify and quantify causal relations among these co-emerging skills. LEARNING OUTCOMES: The reader will be able to: (1) describe how cognition, language, and speech motor control may interact during speech development, (2) describe the associations between speech kinematic characteristics and measures of cognition and language.