Background: Classroom discourse featuring meaning making supports students achieving discipline-specific learning. However, moving beyond recitation requires developing beliefs, skills, structures, and practices. Any theorizing we do about developing discussion practice must attend to realities of culturally and linguistically diverse classrooms. Purpose: Our study offers a teacher education innovation that prepares ELA candidates to facilitate discussion, framed by a set of noticing lenses: noticing for "collaborative communication," "content learning," and "equity." We asked: As they reflected on their first attempts at facilitating discussion in diverse secondary ELA classes, what did preservice teachers (PSTs) notice about their discussion practices and students' engagement and response patterns? Participants: Our study features an inquiry course in a teacher credential program. Participants were 83 PSTs pursuing secondary English credentials, student teaching in diverse classrooms. Three-fifths identified as White, with 39% identifying as PSTs of color. Design: We constructed a database of multipage essays in which PSTs reflected on videotaped discussion tryouts. We developed a coding scheme from research literature and emerging themes from data review to capture what PSTs noticed. We organized themes conceptually using and adapting a multi-lens noticing framework. Additionally, we constructed vignettes to explore ways two PSTs were noticing discussion engagements among their diverse learners. Results: We found evidence of all three noticing lenses in the data. Of the three lenses, collaborative communication was densest. PSTs were preoccupied with "getting students talking." PSTs also reflected on attempts at co-constructing meaning and tracking flow of ideas. Three-fourths documented noticing of crosscontent literacy development. Fewer PSTs demonstrated attending to collaborative interpretation of literary works, an important aspect of ELA-specific discussion. Although PSTs were beginning to leverage cultural and linguistic knowledge, many were not yet responding to or educating about racism and other forms of bias. To demonstrate multi-lens noticing in practice, we present two vignettes of how PSTs interpreted salient moments in classroom discussion. Conclusions: Our research provides a launching for understanding what PSTs notice in early stages of leading discussion and highlights what is needed to jumpstart this process early. Findings underscore the need to build authentic and tangible discussion-leading practice, with deeper attention to ELA disciplinary goals and equity. Our study highlights a framework as an analytical and pedagogical tool to help PSTs organize and reflect on emerging discussion practices. Framework and findings may serve as a heuristic for teacher educators committed to fostering learning about equitable discussion.