Abstract
This paper presents findings of the investigations into perceptions by both students and teachers of Korean about the teacher’s use of learners’ L1 and L2 in classroom settings and aims to provide useful information for a suitable instructional language for a KFL / KSL class. For this purpose, the study conducted a survey and compared perceptions on some key aspects such as roles of the learner’s L1 and L2 in classroom, appropriate point of time or situations for them, languages for classroom activities and non-languages courses, and educational value and effect. Based on the analysis of responses from 27 teachers in Korea and 38 students in Australia, the study discusses a few implications with a particular focus on class management and educational effect.