The teacher might even use the mother tongue to do so. It is an unanimous opinion that the aim of playful activities in the EFL class is the one of promoting enjoyable opportunities for students to communicate among themselves. I will reply stating that more than recipes or someone else's conclusions about a specific topic, developing teachers need questions to think about. Developing teachers need time for reflection so that teaching can be based on principles and promote professional competence. The group who think they know about teaching try to find out more about it in order to tell the teachers about teaching - and that is total reversal.
Teachers are the ones who do it and, therefore, are the ones who know about it.
It's worth getting teachers to build on what they know, to build on what questions they have, because that's what matters - what teachers know and what questions they have. And so anybody who wants to be a helpful researcher should value what the teachers know and help them develop that.