Rich oral language practices, including the opportunity and ability to participate in cognitively and linguistically challenging extended discourse, are foundational to early literacy development. To meet children's needs in their first exposure to the languages of schooling, educators may engage students in extended discourse multilingually. The current study focuses on student-centered translanguaging conversations to examine strategies that preschool teachers employ to support young children's emerging bilingual and biliteracy development in a Mandarin immersion preschool serving primarily non-heritage learners of Mandarin in the United States. Findings indicate that, despite the school's Mandarin-only policy, teachers engaged in covert translanguaging practices to extend and deepen discourse. Specifically, teachers used 13 discourse strategies across two critical areas of schooling: translanguaging for (1) socializing students not just into the Mandarin language but into the norms of schooling; and (2) focusing not just on Mandarin language but also on content area learning. The study concludes with implications for schools and teachers.