While existing research into L2 classroom discourse has highlighted how knowledge and knowledge positions are negotiated, no attention seems to have been paid to what might be called "conceptual epistemic domains." Drawing on 22 hours of video-recorded data from Iranian EFL classrooms, our conversation analytic study illustrates how invoking conceptually accessible epistemic domains creates interactional space for teachers to introduce conditionally relevant vocabulary. We define "conceptual epistemic domains" as areas of world knowledge to which learners have ostensible access. The bottom-up analysis of our data showcases that such practices serve two pivotal pedagogical functions: (1) providing contingent assistance; (2) initiating and maintaining warm-up activities. In the former, the teachers invoke the conceptually accessible epistemic domain facing learners' claims of insufficient knowledge to elicit relevant further talk. In the latter, the teachers sequentially build up a shared conceptual access to conduct a warm-up activity. Both cases unfold interactional space where relevant vocabulary items emerge as learnables. We argue that by bringing to the fore what is conceptually accessible to the learners, teachers orient to relevant vocabulary items as teachable objects. Our findings thus shine light on an interactional resource through which the need for vocabulary teaching is talked into being.