Issues in speech motor control and their relation to the speech of individuals with cleft palate.

A view of speech motor control is presented that is different from conventional coarticulation models. Rather than assuming that phonetic units specify targets for peripheral events, this view is based on holistic behavioral goals. The importance of discovering strategies that organize interactions among physiologic processes of the speech motor system is stressed. The concepts of motor flexibility and plasticity are developed. These motor control issues are used as the basis for discussing the relations among speech motor processes, critical minimum velopharyngeal port size, and speech adequacy in speakers with cleft palate. Different meanings of velopharyngeal incompetency are considered, and a potential misuse of the concept is explained. Finally, the developmental character of motor plasticity is discussed, and the implications of critical periods in speech motor learning are raised for children with cleft palate.