By law, language information of students in U.S. schools must be identified during enrollment. This information affects language screening, federal reporting, provision of services, and so on. In the Florida Heartland, analyses of observations, records, a language inventory (survey), and interviews show that some students and parents’ languages identified during registration are not recorded accurately. Raciolinguistic enregisterment played a role in registrars recording languages as others and in their differential questioning practices; employee training, policy, and the records system design also affected this linguistic re-formation. In the end, Indigenous Mexican languages were under measured by a factor of 19—for every 19 students whose parent spoke an Indigenous language, only one was recorded. Suggestions for improvement are provided.