This study aims to analyze and classify discourse and identify factors possibly causing misunderstandings and mismatches in oral communication in warming-up stage in teaching grammar and expressions for intermediate Korean course and analyze students’ needs to construct effective discourse in the warming-up stage. The study results are as follows: first, analyzing different types of discourse of the warming-up stage based on situations within which communicative interaction takes place or context of shared knowledge, one of the most frequently observed discourse types is where its context is presented, including both the situations where grammar and expressions having similar meanings are provided or none provided, with shared knowledge implicit among teachers and learners. Second, hindrance may occur during the warming-up stage interfering its progress, which could be caused by three factors. The first factor is when a teacher does not provide any context at all or, if does so, insufficiently. The following factor is identified when a student lacks linguistic skills or does not comprehend context of conversation or teachers’ intention. Lastly, it is due to lack of shared knowledge between a teacher and a learner. Third, interviewing of learners to figure out what they need for the warming-up stage reveals that they are aware of the importance of warming-up stage in use of target language during which they expect to be exposed to ample and varied context. This study leads to the conclusion that well-shared knowledge and presentation of situations between the a teacher and learners should be prepared in varied ways in the warming-up stage for efficient teaching method of grammar and expressions. If the analysis of the study be applied in teaching and learning, it would help design more effective course which meets students’ needs. (Kookmin University)