Nature and boundaries of phonologic categories: a case study of an unusual phonologic pattern in a language-impaired child.

This paper presents a detailed examination of an unusual phonologic pattern reflected in the speech of a language-impaired child. The most salient characteristic of this child's speech was the use of [s] in final position of all words except those containing final oral or nasal bilabials. Her pattern seemed best described as reflecting only two canonical forms for word production, CVC and CVCVC, and a dominant word-final category possessing a family resemblance structure with [s] as the prototype. Training was instituted to increase the number of appropriate categories in the child's phonologic system. Training on word-final [f] and [d] was successful. However, training on [d] seemed to result in the creation of a second category with family resemblance structure. The clinical and theoretical implications of this child's phonologic pattern are discussed.