Impact of substitution patterns on phonological learning by misarticulating children

Abstract

Learning and generalization of treated sounds to different word positions is a desired outcome of intervention in the phonologically disordered child's system. Unfortunately, children do not always learn the sound that is treated; nor do they always demonstrate across-word generalization. One possible explanation for differences in treatment outcome may relate to the pretreatment substitution patterns used by different disordered children. This post-hoc analysis of treatment data examines the effects on sound learning and generalization of consistent versus inconsistent substitutes. With a consistent substitute across-word position (CS), the same phone was used in initial, medial and final position for a phoneme that was not in the child's inventory. An inconsistent substitute was evidenced by a different phone for a target sound in each position of a word (InAP), or even within word position (InWP) for an error sound. Fourteen children with severe phonological disorders were treated on an obstruent in initial or final word position. Seven of these children had a consistent substitute for the treated obstruent, two children had variable substitutes across word position, and five children had variable substitutes within and across word position. The analysis revealed a tight relationship between pretreatment substitution patterns and learning. The seven children with a consistent substitute for an error sound learned the sound targeted in treatment and generalized this knowledge to other word positions. Children who had variable substitutes across word position learned the treated sound, but only in the treated word position. Four of the five children in the InWP group did not learn to produce the sound targeted in treatment in any word position. These results suggest that pretreatment substitution patterns may be a predictor of learning and generalization in phonologically disordered children.