In the United States, children of homes where Spanish is the language of interaction often experience what has been termed first language (L1) loss. Nevertheless, there is limited research describing in detail typical patterns of L1 loss in Spanish-speaking children acquiring English as an L2 in this country. No information is available on the relative effects of L1 loss in children with atypical language skills (SLI). Data on the impact of L1 loss in both typical and SLI language learners will provide insight into the factors that affect bilingual children's L1 skills, as well as needed data for identifying language disability in bilingual Spanish-English populations. The purpose of the present investigation is to evaluate the impact that a language contact situation has on the grammatical abilities of bilingual Spanish-English children with and without SLI. Gender agreement was chosen as the focus of this study, as problems in this area have been suggested as possible clinical markers for SLI in Spanish-speaking children exposed to English, but not in children in Spanish-speaking countries. Four groups of Puerto Rican Spanish-speaking children will be followed for two years and their ability to use gender agreement morphemes will be assessed via a variety of measures. Subjects will be divided into the following groups of 20. (1) language majority context with SLI; (2) language majority context with typical language skills; (3) language minority context with SLI; and (4) language minority context with typical language skills. Tasks were developed to assess a variety of linguistic features that impact gender agreement in Spanish. Results will establish patterns of gender agreement use in both typical and atypical learners acquiring language under two different sociolinguistic contexts and bilingual children. These results will also be utilized to extend the research to examine other Spanish grammatical aspects in similar populations.