Karim Shabani - Assistant Professor at Allameh Mohaddes Nouri University
Negar Vahedi - MA Student at Allameh Mohaddes Nouri University

This study investigated the role of student-teacher participation structure (i.e., whole class, small group, and individual) and incidental focus on form in improving L2 learners’ grammatical accuracy in using regular and irregular past tense forms within a mixed method descriptive research design. This study aimed at examining whether occurrence and effectiveness of incidental focus on form would be related to differences in classroom participation structure. A total of 32 pre-intermediate learners between 15 to 20 years of age participated in this study. There were three classes, with three different types of participation structures. Dictogloss tasks were used as the classroom activity. The interactions between teachers and learners in all three classes were observed, audio-recorded, and coded. The focus on form episode (FFE) was utilized as the unit ofanalysis of the focus on form. Finally, an individualized posttest was employed one week after each classroom observation. The results demonstrated that majority of FFEs took place in individual interactions and the proportions of different types of incidental focus on form were not equal according to student-teacher participation structures. In addition, the findings of this study revealed that the effectiveness of incidental focus on form varied across classroom participation structures and in terms of learners’ grammatical accuracy in using regular and irregular past tense forms. In short, it could be inferred that although the majority of FFEs took place in individual interactions, students responded correctly to the higher rate of individualized posttest items that took place in small-group interaction. Therefore, the role of contexts should be considered as an important factor in EFL classes. The findings of this study have implications for teachers who use incidental focus on form in their classroom since they need to be aware of which kinds of incidental focus on form and also which types of teacher-student participation structures would be more effective for improving learners ’grammatical accuracy in EFL classes

accuracy, dictogloss tasks, focus on form episode, incidental focus on form,participation structure