This work-in-progress paper investigates the effectiveness of engagement and content learning of the in-class activities of the Peer Instruction (PI) methodology in an introductory Computer Science course. Moreover, we would like to identify opportunities to improve students’ English skills since the medium of instruction is English but the first language of the majority of the population is not English. Throughout the analysis of a survey of students’ perceptions (N=85), students’ interviews, and in-class observation, we got positive responses in terms of engagement and learning, and we identified opportunities to improve students’ non-native language skills during the in-class PI activities.