Similarities and differences in the lexical-grammatical relation of young dual language learners with and without specific language impairment.

This study examines the lexical-grammatical relation within and across in preschool Latino dual language learners (DLLs) with and without specific language impairment (SLI) using language-specific vocabulary and conceptual lexical-semantic skills. The participants were sixty-one typically developing (TD) Spanish-English speaking DLLs and seventy-four DLLs with SLI from low-income households. Standardized and researcher developed assessment tools were used to measure vocabulary, semantics, and grammar in both Spanish and English. Cross-sectional data were analyzed using hierarchical linear regressions to determine the nature of the lexical-grammatical association within and across languages. The study found significant within-language relations between measures of vocabulary and grammar for both groups. Conceptual vocabulary was a significant predictor for English grammar in both groups. For the SLI group only, both English and Spanish vocabulary scores significantly predicted English grammar and bilingual semantics scores predicted Spanish grammar. These findings underscore the role of language-specific vocabulary on grammatical development and suggest the presence of bilingual bootstrapping in DLLs. However, the degree and nature of cross-linguistic associations vary by language ability and language proficiency. The role of age and nonverbal cognition and clinical implications are also discussed.