This article reports on a cross-institutional, mixed-methods research study designed to gather data on first year writers' language backgrounds at three North American universities. Researchers administered a language survey to 1,870 first year writing students and led follow-up focus groups with 32 participants. Researchers utilized three methods (descriptive statistical analysis, systematic qualitative analysis, and thematic qualitative analysis) to analyze numerical survey responses, written survey responses, and focus group transcripts. Results include both quantitative and qualitative findings, featuring one extended case study that incorporates all three data sources to richly detail the article's argument: while language surveys are conducted to understand changing populations, they reify language backgrounds in the labeling act, thereby constraining language identities more complex than institutional language allows. The article features rather than obscures this tension, including student resistance to the survey as data reveal how students co-opt, adopt, and resist the language identities supplied to them.