Abstract In this article, which constitutes the concluding article of the TASK Special Issue on teacher education, I reflect on the cognitive frictions that many pre-service and in-service teachers experience when they are informed about the basic principles behind task-based language teaching and are invited to work with tasks, or design them. More in particular, I describe cognitive frictions between three types of ‘knowing’ that drive teachers’ decision-making in the classroom: their personal intuitions about language learning and teaching, the theory and research-based insights they gain access to, and the data-driven knowledge that accumulates from gathering empirical data about life in their classroom environment. I will claim that the frictions that are bound to arise between those three types of knowing are inevitable, and may even be considered as inherent to the profession of (language) teaching. What is more, they can be fruitful in terms of fostering teachers’ professional growth, particularly when they get the chance to discuss those frictions with others. The communication about such frictions I will dub ‘communifriction’ in this article. Drawing on the articles included in this special issue, I describe a range of different ways in which communifriction can take shape and can become beneficial for teachers’ own professional development and for the implementation of task-based language teaching.