Quantifying phonological knowledge in children with phonological disorder

Abstract

Generative phonologists use contrastive minimal pairs to determine functional phonological units in a language. This technique has been extended for clinical purposes to derive phonemic inventories for children with phonological disorder, providing a qualitative analysis of a given child’s phonological system that is useful for assessment, treatment, and progress monitoring. In this study, we examine the single-word productions of 275 children with phonological disorder from the Learnability Project (Gierut, 2015b) to confirm the relationship between phonemic inventory–a measure of phonological knowledge–and consonant accuracy–a quantitative, relational measure that directly compares a child’s phonological productions to the target (i.e. adult-like) form. Further, we identify potential percentage accuracy cutoff scores that reliably classify sounds as in or out of a child’s phonemic inventory in speech-sound probes of varying length. Our findings indicate that the phonemic function of up to 90% of English consonants can be identified from percentage accuracy for preschool-age children with phonological disorder when a sufficiently large and thorough speech sample is used.