The urgency for education to participate in the plan of action of the UN 2030 Agenda for Sustainable Development (SD) poses challenges to language education in university language centers. This paper discusses the potential of Higher Education (HE) language center courses to provide students with the knowledge and skills of inclusive, respectful, and equal communication needed in promoting SD and global citizenship. Education for sustainable development (ESD) in language teaching often focuses on integrating the content of SD topics into the language course. This paper focuses on the skills dimension and reports on a case study of a dialogue approach, a pedagogical method that could be central in ESD. A two-credit optional B2-C1 CEFR level university English course with the name "Dialogue: Constructive Talk at Work" is described to give a practical example of how to bring ethical thinking and interaction into an HE language classroom, by introducing the ethical concepts of Bohmian dialogue to students, and by creating a safe place for them to practice ethical dialogue through English as a lingua franca (ELF). The reflections of one group for this case study were analyzed to show how a dialogue approach to teaching ethical communication, interaction and collaboration can raise students' awareness of using ELF in ethical dialogue and perhaps transform their ways of thinking and interacting. The student reflections showed that the pedagogical dialogue method has potential in developing abilities needed in ESD as well as in working life.