Contributions of the study of disordered speech to speech production models

Abstract Acoustic and perceptual data have been obtained from the speech of individuals with several types of disorders. For two groups of individuals, the deviant speech arises from anatomical changes: surgical modification of the configuration of the nasal passages in one case, and the presence of nodules on the vocal folds in the other. Two other groups exhibited deviant motor control of speech: severely hearing-impaired children, and adults with neurogenic disorders. In each of these groups, the disordered speech exhibited ranges of acoustic or articulatory characteristics that were beyond the normal ranges. Perceptual evaluations of these utterances have helped to delineate the ranges that might be considered normal, and the results of these studies have contributed to the refinement of speech-production models.