With the growing interest in interaction in EFL classrooms, task repetition plays an important role in facilitating interaction in classrooms. This study used a quasiexperimental pretest and posttest design measured the effect of task repetition through L1 (Persian) use and the functions it serves a group of lower intermediate female students aged 12 to 15 (N = 20) who were learning English as a Foreign Language (EFL) in Iran. The experimental group was divided into two groups: Group A (Exact Task Repetition Group) (n = 10) and Group B (Procedural Task Repetition Group) (n = 10). The third author trained both groups for 12 sessions. Every session lasted about 30 minutes. They worked on the story-telling task. The students’ performance in pretest and posttest was audio-recorded, and then was transcribed, the number of c-units and L1 c-units produced by every group in pretest and posttest was counted. The functions that the L1 served, was also considered very carefully. The results reveal that i) task repetition decreases L1 use, and ii) it also has an effect on the functions like appeal for help or borrowing that the L1 use serves.
