Teaching large language classes presents unique challenges in maintaining engagement and personalized instruction. This study explores innovative approaches through a qualitative case study of LANG1234: Professional Speaking for the Workplace, an English for Specific Purposes (ESP) course at a Hong Kong university designed to develop professional communication skills across disciplines in a large class size format. Grounded in the ESP principle of addressing learners’ specific professional needs, the course features modules on branding, crisis communication, and intercultural competence. Drawing on instructor reflections and course documents, the paper examines how co-teaching models, technology integration, and active learning strategies are deployed to overcome the constraints of the large-class format. Findings indicate that collaborative co-teaching, digital tools (e.g., Miro, Mentimeter), and structured interactions successfully foster an interactive, skills-based learning environment. The study also identifies key challenges, including instructor role ambiguity and the ‘disjuncture’ of teaching profession-specific content, underscoring the need for structured professional development to support ESP educators in effectively scaling interactive, communicative language instruction.<br/><br/>