Building vocabulary in two languages: An examination of Spanish-speaking Dual Language Learners in Head Start

• We examined English and Spanish vocabulary among Head Start Dual Language Learners.
• In fall and spring, children knew more about the language they heard most at home.
• Classroom instruction predicted Spanish and English vocabulary learning in Head Start.
• For English learning, the role of instruction was strongest for those with low initial skills.

This study examines the English and Spanish vocabulary skills that young Dual Language Learners (DLLs) bring to Head Start, as well as their vocabulary learning over the year. Further, we isolate the unique contributions of various child, family, teacher, and classroom factors to these skills. Participants were drawn from a recent cohort of the Head Start Family and Child Experiences Survey. Results show that, for both Spanish and English vocabulary, child and family factors, especially the prevalence of each language in the household, play a role in initial skills and end-of-year skills. The quality of the language of classroom instruction also predicts Spanish and English vocabulary learning over the year for all children; in English, this relation is significantly greater for children with the lowest initial skills. Findings elucidate potential leverage points for intervention to improve Spanish and English vocabulary outcomes during Head Start for these vulnerable early learners.