This chapter draws on dialogic language and literacy education, focuses on writing – specifically on students’ thinking and linguistic decision-making in writing. It considers the limitations of binaries which position authoritative and dialogic talk as opposites and offers a critical reframing of the role of teacher as expert in dialogic teaching. The chapter shows that dialogic teaching which effectively promotes metalinguistic understanding and the capacity to think metalinguistically requires teachers to orchestrate metalinguistic discussion in a way which draws on both teacher-as-expert and teacher-as-facilitator. It addresses the significant gap in research on dialogic teaching specifically related to writing. The chapter argues that for the critical importance of dialogic teaching in opening up metalinguistic talk about linguistic choice in written text. M. A. K. Halliday describes becoming a more proficient language user as a process of learning how to mean: arguably, a process in which metalinguistic understanding needs to be activated and in which dialogic teaching can be a powerful enabler.