The school-readiness gap for Latino dual language learners in the United States has been well documented, despite a strong research base highlighting effective strategies and practices for supporting their academic success. However, current educational practices reflect the hegemonic discourse that, because the United States is an English-speaking country, English should be the language of instruction. Additionally, educational research during the past decade has been characterized by an emphasis on the use of rigorous experimental designs that are highly generalizable and fail to take into consideration the role of teacher beliefs on classroom practices. This study used a cultural communities lens to explore the beliefs about classroom language use of two Head Start teachers in order to gain insight into how teacher beliefs influence classroom practices, particularly the language of instruction. Analysis of teacher interviews and assessments of classroom language use indicated that teachers had very different beliefs about language use, despite their coming from very similar ethnic and linguistic backgrounds, and that these beliefs were translated into classroom practice. Teacher beliefs were grounded in teachers' experiences as members of cultural communities, and the findings highlight the need to attend to within-group variability as well as classroom processes that influence teaching and learning.