This study investigates differences in classroom activities and teacher talks in differentiated TEE classes. One middle school teacher and her two classes in Grade 8 participated in the study. Around half of the participants were in a higher-proficiency class whereas others were in a lower-proficiency class. One lesson from each class was videotaped and then transcribed. The transcribed data were analyzed and compared in terms of classroom activities the students performed and teacher talks. In the higher-proficiency class, the teacher used more fluent and complex English and used more difficult classroom activities than the other class. In the lower-proficiency class, however, the teacher used more Korean and used much more repetition than the higher-proficiency class. In addition, the teacher frequently asked the lower-level students what the meanings of target English words were in Korean and elicited more target English words from them. The teacher helped the lower-level students to understand the target English words and provided them with the chance to produce the target words.