Anticipatory coarticulation and aphasia: implications for phonetic theories

Abstract

Studies of clinical populations usually (1) track more variables than in studies of normal subjects and (2) encounter a high degree of behavioral variability, making generalization difficult. However, these apparent limitations may in the long run prove to be strengths. For example, in studies of normal talkers variability is often treated as noise against which the size of an effect may be measured, while in studies of disordered talkers the extent of variability itself may be an important goal of inquiry. Information obtained from clinical populations has proven valuable in addressing the neuroanatomical substrates and functional organization of speech. This review focuses on recent studies of anticipatory coarticulation in the speech of focally-lesioned aphasic talkers, examining how these data address the neural representation of language processes, the role of suprasegmental units (e.g., the syllable) in speech production, and the manner in which coarticulatory variability is perceived by normal listeners. The reviewed data indicate that the variable speech of clinical populations does not necessarily pose an impediment to research, but rather constitutes an important database from which further understanding of normal and disordered speech processes may be obtained.