This article explores the use of conversation analysis (CA)-informed speaking task design to develop second language (L2) learners' interactional repertoires in L2 classrooms. The study draws on the voices of teachers and Japanese learners of English as a foreign language (EFL) who encountered difficulties or dilemmas in L2 interaction due to cross-culturally different interactional rules. It focuses on developing L2 learners' repair strategies to enhance their interactional repertoires in relation to the reasons behind classroom silence. The study regards silence and learner-initiated repair as intertwined interactional resources frequently occurring within the same sequence but with distinct functions. Silence functions as an interactional cue, preluding forthcoming repair, whereas repair practices can play a crucial role in the progress of interaction. CA-informed pedagogical approaches help learners to self-mediate classroom silence and thereby promote interaction, by encouraging them to use repair strategies. This study presents a framework for developing CA-informed material through a needs analysis, reflective observation of L2 interaction, and learner-initiated repair. It aims to raise awareness of essential interactional repertoires rarely explored in English language teaching (ELT) material design. It suggests that ELT material adopting CA perspectives can be an indispensable bridge mediating classroom interaction.