This is a qualitative case study that explores conversational interactions during book-reading practices in a Mandarin-speaking Chinese American family between the mother and her two young children. The study employs a sociocultural lens and the concept of translanguaging to describe the characteristics of interactional practices during book readings in a bilingual family with young children. Through discourse analysis of the book reading interactions, we found that translanguaging acted as a bridge to comprehension and served as a window to mental imagery that allowed participants to refine their understanding of the texts. We draw implications for teachers working with emergent bilingual children, particularly on the role of heritage languages in promoting biliteracy development in young emerging bilingual children.