While language hegemonies often take the form of one language imposed upon speakers of another, this article focuses on the hegemony of language boundaries themselves imposed upon everyday language practices, and in particular, upon those of teachers and students in bilingual classrooms. This examination of two different borderland contexts--El Paso, Texas on the U.S.-Mexico border and a central Paraguayan community on an urban-rural Spanish-Guarani speaking border--illustrates how similar dominant ideologies and discourses worked in both places to make it seem as if what participants saw as "language separation" was pedagogically and socially superior to what they saw as people's everyday "mixed" language use. While teachers' languaging in practice refused these boundaries, it remained unaffirmed by any explicitly positive discourse. With others, I argue that discourses that explicitly affirm and valorize translanguaging practices must become more available to teachers as ways to name, understand, and evaluate their own (and students') language use. And specifically, here I highlight the embracing of translanguaging in formal, public events beyond the classroom as key to this process, illustrating this proposal with two such moments in the El Paso and Paraguayan borderland contexts.