Diagnostic Accuracy of Grammaticality and Utterance Length in Bilingual Children

Abstract

Purpose: The purpose of this study was to investigate the diagnostic accuracy of two measures derived from spontaneous language samples, mean length of utterance in words (MLUw) and percentage of grammatical utterances (PGU), in identifying developmental language disorder (DLD) in Spanish–English bilingual children. We examined two approaches: best language and total language. Method: The participants in this study included 74 Spanish–English bilingual children with ( n = 36) and without ( n = 38) DLD. Language samples were elicited through a story retell and story generation task using Frog wordless picture books in English and Spanish. Stories were transcribed and coded using the Systematic Analysis of Language Samples (Miller & Iglesias, 2020) to extract MLUw and PGU in both languages. Results: Logistic regression analyses suggested that a model that included PGU, MLUw, and age achieved the best diagnostic accuracy in predicting group membership. Both approaches, best language and total language, had fair diagnostic accuracy. Conclusions: In combination, PGU and MLUw seem to be useful diagnostic tools to differentiate bilingual children with and without DLD. Clinical implications and usability are discussed.