As conceptualized in Vygotsky’s (1978) theory of mediation, the present quantitative study scrutinized the impact of explicit and implicit mediators on high school students’ L2 listening anxiety and listening comprehension. Over six months, two groups of 34 Iranian high school students were exposed to pronunciation instruction (explicit mediator-using phonetic rules- and implicit mediator-without phonetic rules), and a control group of 17 students received no pronunciation instruction. Pretests and posttests were used to measure learners’ improvements in listening anxiety and comprehension. Small changes were observed in both variables for the control group, whereas significant progress was found for both experimental groups, especially the explicit group. The results revealed that pronunciation instruction is a meaningful mediator in developing listening comprehension and decreasing listening anxiety among high school students, even when instructional time is restricted. This study has some practical implications suggesting that Iranian school teachers and book designers should consider pronunciation instruction effects when teaching listening to school students. Manuscript profile

Communication in English and critical thinking are two essential 21st-century competencies. A variety of teaching and learning techniques are being developed to equip students with these skills and meet the challenges of global competition. Critical thinking skills should be developed and transferred through education, but there are few empirical studies available to help educators decide how to enhance critical thinking in the classroom. Accordingly, the present mixed-methods study scrutinized the impact of explicit and implicit pronunciation instruction on the critical thinking and listening comprehension of English language learners. Over 6 months, two groups of 34 English language learners were exposed to pronunciation instruction (explicit mediators using phonetic rules, and implicit mediators without phonetic rules), and a control group of 17 students received no pronunciation instruction. Pre-tests and post-tests were used to measure learners’ improvement in critical thinking and listening comprehension. Moreover, semi-structured interviews were used to show the participants’ reflections regarding pronunciation instruction. The results of the data analysis revealed no significant change for the control group, but significant progress was found for both experimental groups’ listening comprehension and critical thinking, especially the explicit group. Besides, the qualitative analysis showed that pronunciation instruction increased phonological awareness, listening improvement, and a sense of being analytic among participants in the explicit pronunciation group. Moreover, pronunciation instruction increased listening improvement among implicit pronunciation group participants. In brief, the findings suggest that helping students learn critical thinking skills does not require a comprehensive reorganization of the high school curriculum. It is possible to offer a critical thinking program like this during the school day without seriously disrupting the school’s already full schedule. Manuscript profile