The conditions and course of clinically induced phonological change.

This two-part study continued the evaluation of minimal pair treatment in phonological change (Gierut, 1989, 1990, 1991a; Gierut & Neumann, 1992). Three linguistic variables relevant to change were experimentally manipulated within an alternating treatments design to determine specifically the interplay of a maximal number of feature distinctions, feature class, and relationship of treated phonemes to a child's grammar in inducing sound change. The conditions of treatment that were shown to facilitate optimal phonological change in previous research were again experimentally replicated. Specifically, minimal pairs comparing two phonemes previously unknown to a child that also differed by maximal and major class features were found to be the preferred context motivating change. Important individual differences emerged and underscored the role of a child's pretreatment grammar in phonological change. These differences contributed to descriptions of possible courses of change followed by children with phonological disorders and bear upon the predictability of change and the effectiveness of treatments that may condition change.