Regardless of the appreciation of language learners’ achievement in task-based language teaching, not much has been hinged upon learners’ perception and reception of various elements. This study examined task complexity and modality effects on Iranian EFL learners’ comprehension of task difficulty, competencies, and difficulty-skill balance as well as the learners’ task experience. The Flow Outlook features were also applied to investigate how difficulty-skill balance anticipated flow experience. Via a repeated-measures design, and with a focus on task complexity (simple vs. complex) and task modality (written vs. spoken), 49 EFL learners carried out four argumentative tasks (two simple written and spoken vs. two complex written and spoken tasks); then, they ticked the flow questionnaire to gauge their perception of task difficulty, competence, and task experience. Repeated-measures MANOVA revealed although task complexity influenced task difficulty and difficulty-skill balance significantly, the skill was not affected significantly; task modality influenced task difficulty and skill significantly while difficulty-skill balance received no significant effect. The follow-up post hoc test indicated that complexity and modality significantly influenced flow, attention, and control, but not interest. Linear regression revealed difficulty-skill balance was a predictor for learners’ flow experience for both writing tasks and simple speaking task but not for complex speaking tasks. Pedagogically, the findings of this research may have some implications for English language teachers, learners, and materials developers.
