Characterizing the Growth in Utterance Length, Grammaticality, and Subordination in Spanish and English in Bilingual Children

Purpose: The aim of this study was to examine the growth of utterance length, grammaticality, and subordination in Spanish and English in bilingual children with and without developmental language disorder (DLD). Method: This is a longitudinal study of 100 children (DLD, n = 43) who were followed for 2 years with three testing times. At Time 1, children were, on average, at age 5;10 (years;months; SD = 12 months). Children produced spontaneous language samples in Spanish and English using a story retell and a story generation task. Language samples were transcribed and analyzed using the Systematic Analysis of Language Transcripts. Mean length of utterance in words (MLUw), percentage of grammatical utterances (PGU), and subordination index (SI) measures were calculated in Spanish and English. Growth curve modeling was used to analyze the data. Results: Similar growth trajectories were observed for MLUw and SI in both Spanish and English. These measures increased over time. However, PGU showed a different growth trajectory in Spanish and English. English PGU increased significantly, while Spanish PGU change was minimal. Children with DLD underperformed compared to children without DLD on all measures at the onset of the study, but their growth trajectories did not differ. Conclusions: Sentence development in bilingual children with and without DLD was characterized by increases in utterance length and use of subordination. However, grammaticality increased only in English. Clinicians should be aware of this developmental trend while conducting language evaluations in bilingual children.