This article examines the intersection of language enumeration practices in the Indian Census and the shaping of the Three Language Policy (TLP) in national educational planning. Drawing on census documents, government reports, and policy frameworks, the study traces how census categories, rationalisation methods, and thresholds influence which languages gain visibility and legitimacy in educational policy. The paper identifies how enumeration practices, particularly the flattening of mother tongues in post-enumeration processes, contribute to a constructed sociolinguistic reality that favours scheduled and official languages while marginalising others. Through a critical analysis of census questionnaires from 1961 to 2011, and a review of key planning documents such as the National Education Policy (NEP) 2020, the National Curriculum Framework for School Education (NCFSE) 2023, National Commission for Religious and Linguistic Minorities (NCRLM) reports and post-census reports, the study shows how linguistic hierarchies are institutionalised in state policy. The paper argues for greater transparency in census codification methods and calls for the inclusion of multilingual realities in both enumeration and educational frameworks. By foregrounding enumeration as a site of language policy in action, the article contributes to rethinking how language data shapes and constrains policy decisions in multilingual nations like India.