Most U.S. educational reforms have narrowly focused on how to improve the ways in which students use language, and most specifically English. But in the last two decades, it is something called "academic language" that has permeated all education discourse. Here we discuss the development of the construct of academic language and the pernicious effects it has had on Latinx minoritized bilingual students. We focus on how academic language is being used to enregister Latinx students as "non-academic," ignoring bilingual Latinx epistemologies and ways of languaging. We interrogate the rigidity of the linguistic borders that have been drawn around the concept of academic language, linking it to the epistemological and ideological orientations about language as an autonomous entity produced by colonialism. We show how standards and other educational products are being used to police linguistic borders that are increasingly responsible for the failure of Latinx bilingual students.