Language learning is an important developmental experience for young children during their preschool years, and book reading is an important context for promoting this growth. Book reading introduces children to a wider range of words than is evident in typical conversations and provides meaningful opportunities to practice using new words in conversations with peers and adults to support vocabulary development. However, rather than just assuming that the frequency of book reading is important, the quality of the adult's reading style is believed to be most influential to foster children's vocabulary learning. In the present study, conversation analysis was applied to analyze teacher-child language interactions during whole-class repeated book reading in two preschool classrooms. Using detailed transcripts of book reading activities, the study examined the core practices for vocabulary learning as observed in classroom talk. Exploring classroom interactions in such detail can inform early childhood educators about how to promote vocabulary development in their classrooms by incorporating these practices.