Language surveys and censuses have long occupied a privileged position in language planning and policy (LPP) as sources of authoritative empirical evidence, mostly treated as neutral instruments of measurement. This special issue advances a reconceptualisation of language surveys and censuses as constitutive instruments of language governance. Drawing on classic LPP theory, Language Management Theory, and critical scholarship, the collection theorises enumeration as a site where linguistic knowledge, ideology, power, and policy intersect. Across twelve contributions spanning five continents and diverse sociopolitical contexts, the special issue examines how language surveys and censuses actively construct linguistic realities through classificatory design, produce epistemic authority through institutionalised standards of reliability and validity, organise relations of power and agency among states, experts, and speakers, and generate durable policy consequences. To integrate these insights, the introduction proposes a four-domain analytical framework – design and representation; reliability and validity; power, interests and agency; and policy consequences – through which enumeration can be systematically analysed as a mode of language governance. By repositioning language surveys and censuses at the centre of LPP theorisation, this special issue contributes to a deeper understanding of how linguistic orders are produced, contested, and governed through numerical knowledge in the modern state.