The present study considers how novice teachers become language policymakers in linguistically hegemonic schooling contexts. We used critical discourse analysis (Fairclough, 2010) for transcribed interviews and classroom observation data from preservice teachers, purposively sampled from three different university-based science teacher education programs in Arizona and California. At the time of our study, these states shared common hegemonic English-only instructional policies (California’s Proposition 227, Arizona’s Proposition 203), with Arizona most robustly enforcing its restrictive language policies. However, the Englishonly policies of both states racially marginalized Latinx students and created often insurmountable barriers to English learners’ abilities to enroll in the advanced science coursework required for high school graduation and/or university admissions (Gamoran, 2017; Tolbert, 2018). Our analysis reveals paradoxes in how both teacher ideologies and institutional policies converge to systematically marginalize emergent bilingual students in science and schools. We focus our analysis on what this means for preservice teachers as they become language policymakers in linguistically diverse settings.