Voice as Pedagogy: Enhancing EMI Teachers', Self-Efficacy, Instructional Clarity, and Vocal Health Literacy Through Integrated Voice Training Workshops

English-Medium Instruction (EMI) teachers often face vocal fatigue and difficulties in clarity when they speak a lot in a second language without proper training in voice use or vocal health. This mixed-methods study looked at the effects of a 1-day, 6-hour integrated voice training workshop that combined vocal health literacy with teaching voice techniques. Thirty university EMI instructors took part in a single-group pre-post design, completing a Vocal Health Literacy Survey and the 12-item Teachers’ Sense of Efficacy Scale (TSES), and sat for semi-structured interviews. Quantitative results showed significant immediate improvements in vocal hygiene (P < 0.005), preventive strategies, and symptom recognition, although some of this improvement faded by the 3-month follow-up. Self-efficacy scores rose modestly (pre: M = 6.07, post: M = 7.93), but there was no significant correlation with vocal health literacy. Thematic analysis of semi-structured interviews revealed seven key themes: metacognitive vocal awareness, discipline-specific adaptation, contextual barriers, student-led reinforcement, emotional resilience, technological mediation, and self-reported vocal fatigue. These highlight both the supports and challenges teachers face in using these strategies over time. Importantly, teachers reported fewer requests from students for clarification after the workshop, suggesting that instructional clarity improved. These findings emphasize how frameworks of embodied pedagogy and health literacy can empower EMI teachers, enhance vocal well-being, and promote clearer instruction. Recommendations include periodic booster sessions, institutional support for voice care policies, and the use of amplification technologies to maintain long-term benefits.