This brief has focused on language use in the preschool classroom—in particular, teachers’ use of English and the home language(s) of the DLLs they teach and interact with. Many classrooms reported using a substantial amount of DLLs’ home languages in the classroom, and FCCHs tended to report more home language use than center-based classrooms. We generally found positive relationships between classroom use of the home language and child outcomes. (author abstract)