I interrogate how consequential representations of student characteristics are fashioned by analyzing identification, recording, and reporting of student and parent language, race, and ethnicity in K-12 school registration, school records, and state reporting. In the Florida Heartland, analysis of ethnographic school observations, school electronic records, a language inventory (survey), interviews, and official state data show that language, race, and ethnicity information for some K-12 students and parents (especially indigenous Mexicans) collected during enrollment are not recorded accurately and undergo transformation from collection to reporting. According to my language inventory, students' parents were indigenous language speakers 19 times more often than reflected in raw school records. In records from the local middle school, 10 percent of students were American Indian, though the state reported this as 0 percent. This linguistic and racial re-formation resulted from several factors, including registrars recording languages as others (i.e. Spanish instead of Náhuatl), differential questioning practices, and state reporting policy. As discussed, enhanced procedures and updated policy should improve areas affected by inaccurate data.1. Introduction. Student demographic information, such as language, race, and ethnicity, is consistently quantified in US educational institutions after it is gathered during school registration. Representations of this demographic information are then used in a myriad of consequential ways, including during making decisions on affirmative action programs, investigations into school segregation (NCES 1996; Renn 2009), balancing classrooms, investigations of discrimination in ability grouping (Lopez 2003a; Vizcarra 2017), federal and state reporting of student progress by aggregated sub-groups, screening children for language services, informing culturally sustaining pedagogies (Paris and Alim 2014), and accessibility in school-home communication. Prior research has examined issues surrounding school registration interactions and the subsequent quantification of student characteristics (e.g., Baquedano-López . Yet none highlight the important site of the on-the-ground micro processes that occur during school registration, tracing it all the way to codified reporting at the state level, as the present study does.In investigating how representations of student and parent language, race, and ethnicity are constructed by schools and the state, I introduce the terms 'linguistic re-formation' and 'racial reformation' as theorization tools. With roots in Omi and Winant's (1986) 'racial formation', the terms respectively describe the processes of transformation that characteristics (i.e. language, race, and ethnicity) reported by students and parents may undergo by the time the information is used at school or in state reports. With this in mind, this study showed: