Phonological complexity in intervention for Spanish-speaking children with speech sound disorder

The efficiency of intervention for children with speech sound disorder may be influenced by linguistic complexity of the phonological intervention target. Complex targets, particularly, later-acquired, less-known consonants and consonant clusters, have been linked to greater post-intervention generalization to untargeted phonological structures. Yet there is little direct evidence to support target selection based on linguistic complexity for Spanish-speaking children with speech sound disorder. This intervention study utilizes an experimental single-case design to examine the efficacy of intervention in Spanish using different complex targets (i.e. /ɡɾ/, /bɾ/, and /l/). For each of the four Spanish-speaking children with speech sound disorder, sounds at 0% accuracy during baseline were monitored across the baseline period, during and post-intervention, and at one- and two-month follow-up visits. Over the course of intervention, only one participant achieved mastery of the targeted structure in practiced words. However, all participants demonstrated some amount of broad phonological generalization to untargeted consonants or clusters. Variable learning trajectories and broad phonological generalization are discussed as they relate to participant characteristics and linguistic complexity.