RESUMO
PURPOSE: Percent grammatical utterances (PGU) provides clinicians and researchers with meaningful information on young children's grammatical abilities (Eisenberg & Guo, 2016). However, work is still needed to place PGU within the context of conventional language sample measures and understand how PGU reflects grammatical development in bilingual populations. The current study focuses on Spanish-English bilingual preschoolers to examine: 1) change in Spanish and English PGU over one year of preschool English instruction, 2) associations between PGU and other language sample measures within each language and across time, and 3) the types and frequency of error patterns in each language. METHOD: Play-based language samples were elicited in English and Spanish from bilingual children (n = 19) at the beginning and end of an instructional preschool year in English. PGU was derived from each sample along with other language sample measures (e.g., mean length of utterance). We examined change in PGU from Time 1 to Time 2, and correlations between Time 1 PGU and Time 2 PGU for each language. Specific grammatical errors were described in terms of their frequency in each language and stability across time. RESULTS: Average English PGU increased from Time 1 to Time 2, and correlated with other language sample measures. Conversely, average Spanish PGU did not increase from Time 1 to Time 2, nor did PGU correlate with any other Spanish measure. Error patterns in each language reflected grammatical differences across English and Spanish. CONCLUSIONS: Our results revealed distinct developmental patterns in bilingual children's first and second languages. Associations between time points and measures in English contrasted with disassociations in Spanish. Error patterns revealed more detailed information as to how bilingual children begin to acquire grammatical structures in each of their languages. We provide a case example to illustrate how grammaticality and error patterns can be used to characterize children's language abilities. We conclude with clinical implications of grammaticality in Spanish-English bilingual children.