This study examined the relationship between sign language training, teachers’ attitudes toward inclusion, and communication confidence in teaching Deaf and Hard of Hearing (DHH) students. Despite initiatives to implement inclusive education, teachers often face challenges in acquiring and applying sign language skills, affecting classroom effectiveness. A descriptive-correlational design was employed involving 89 teachers handling DHH learners. Data were collected using a structured questionnaire measuring the extent of sign language training, attitudes toward inclusion, communication confidence, and challenges in skill application. Quantitative data were analyzed using weighted mean and Pearson’s correlation, while qualitative responses were thematically analyzed. Most teachers were female, aged 30–39, with varying teaching experience and educational backgrounds. Teachers generally underwent moderate to high sign language training, exhibited highly positive attitudes toward inclusion, and demonstrated strong communication confidence in linguistic competence, interactive communication, instructional delivery, and adaptability. Significant positive relationships were observed between the extent of sign language training, attitudes toward inclusion, and communication confidence (r = 0.612–0.721, p < .001). Challenges included balancing workload with training, limited access to learning materials, and sustaining fluency in classroom application. To address these issues, the study proposed Project S.E.N.Y.A.S, a training program aimed at enhancing teachers’ attitudes, skills, and instructional effectiveness. Findings indicate that professional development in sign language significantly strengthens teachers’ communication competence and inclusive practices. Structured, practical, and continuous training is essential to improve teacher preparedness, learner engagement, and inclusive classroom outcomes.