This article reports the discursive processes of language play (LP) construction in an elementary school EFL classroom in Korea. It was found that teacher/learner agency and the LP production affected each other bi-directionally in intricate ways. Also, the LP production was found to be linked to teacher authority and inter-student power relations. The moment-to-moment shifts in attitudes on the teacher's and students’ parts resulted in the (re)emergence of agency which decided the direction of the practice of LP production, i.e., motivating or demotivating interactants to create LP. Regarding the students’ contextually situated EFL learning outcomes, the ludic function of the LP added to an amelioration in the outcomes.