In the article, the term ways of communicating refers to the many ways in which oral and written communication functions in contexts inside and outside of school. It also refers to one of eight categories in a didactic model which has been constructed in order to provide a solid foundation for the description of classroom practices. The aim is twofold: on the one hand to argue for the collaborative development of theoretical didactic models based on the comparative approach and on the other hand to introduce ways of communicating as a category highly relevant for the understanding and description of classroom practices. Drawing on the works of researchers in the fields of discourse analysis, literacy and educational sciences, the main point is that the discipline-specific ways of knowing and doing should not be seen as separate from the ways in which communication takes place inside the disciplines. Within this point of view, didactic research should focus on the processes of recontextualising (Basil Bernstein 1996) through which disciplinary knowledge and methods are transformed from domains outside school into classrooms inside school, i.e. from disciplinary to school-only ways of communicating. Some examples from literature and science classrooms are given to provide a basis for reflecting on and discussing the interplay between disciplinary knowledge and practice and the ways of communicating in classrooms.