Preschool teachers should use specific discourse strategies to meet the unique needs of dual language learners (DLLs). The absence of research on teachers' use of discourse strategies with DLLs is partially due to the lack of measurement tools. This study describes the discourse language environment of preschool classrooms. It tests the factorial structure of a child-level observational measure of teacher's discourse strategies – the DUALLS – and associations with bilingual receptive and expressive skills and self-regulation skills in a sample of four-and five-year-old DLL children (n = 152) across 38 classrooms. Factor analysis revealed two factors: (1) didactic and language modeling; and (2) elaborative and responsive. Preschool teachers' use of didactic and language modeling strategies were positively related to children's bilingual expressive vocabulary skills and negatively related to children's positive engagement. Preschool teachers' use of elaborative and responsive language was positively related to children's positive engagement. (author abstract)