This study uses a language socialization approach to explore the role of Ukrainian language instruction in the revitalization of Ukrainian as the national language. Based on 10 months ethnographic observation and videotaping of classroom interaction in two fifth-grade Ukrainian language and literature classrooms, it focuses on corrective feedback targeting children's use of Russian forms and considers how these practices are shaped by the imperatives of Ukrainian language revitalization and language ideologies that valorize "pure language" as the sole legitimate variety of Ukrainian. The analysis reveals how corrective feedback is socializing children into speaking pure language and into dominant Ukrainian language ideologies that proscribe language mixing as a violation of the natural boundaries between languages, thus preserving a distinct Ukrainian language as an emblem of a distinct Ukrainian nation.