In this interaction, Manuel and Rico (all names are pseudonyms) expertly mix Spanish and English to communicate as they collect data in a ninth grade physics lab. Your reaction to this mixture of English and Spanish, what users sometimes call “Spanglish” will depend on your beliefs about language and multilingualism. Researchers refer to these beliefs as language ideologies (Gal and Irvine 2019). Due to the absence of clearly articulated language policies in the United States, in districts, and in schools, teachers set the policies for their classrooms and hold students accountable for following or not following these policies based on their language ideologies (Zhang and Pelttari 2014).