Arizona State University is partnering with three Head Start classrooms to examine how bilingualism in language minority Head Start students predicts social and cognitive aspects of school readiness. Specifically, the studies will: (a) describe variations in bilingualism by using extensive assessments of early oral English and Spanish development; (b) plot the trajectories of Spanish and English oral proficiency and examine these in relation to trajectories of social and behavioral competence; and (c) investigate the relation between language minority children's Spanish and English oral proficiency and their early school adjustment. Participant will include 4 year-old Head Start preschool children from Spanish-speaking homes. Observational and behavioral data were piloted in Year 1 and data collection will occur in Years 2-3. It is expected that target children will improve their proficiency in English and improve or maintain their Spanish proficiency. Children with high English proficiency and those with large gains in English proficiency are expected to have the best academic outcomes, and children with high proficiency in both English and Spanish are expected to have higher levels of social competence.