Variability in speech dyspraxia.

In a volume dedicated to Professor Crystal, this study takes up some remarks of his (1982) regarding definitions of disorders and use of day-to-day clinical data. The topic chosen relates to the notion of variability in speech dyspraxia. Several different uses of the term are noted, but the one used in this paper focuses on variability of errors in a given word on a repeated-trials task. This task was employed to investigate whether, as previously claimed, speech dyspraxics differ from other pronunciation-disordered groups in terms of error variability. Results indicate that as a group they differ from spastic dysarthrics, but not from phonemic paraphasic speakers. On an individual basis, divisions are not as clearcut. Implications for assessment and speech production are considered in the light of this.