For loads of us in a (largely) monolingual EFL setting, there is an amazing resource available under our noses. I’d argue that a lot of people feel it’s a bit rude but I’m going to argue that rude or not, you get to maximize engagement in lessons through greater relevance and also at least partial schema activation.
Eavesdropping on your learners when they’re using L1.
If you can do it, this pays dividends. You get to give them what they are already thinking about but may not be able to do in English. For example, are people on your business class complaining on the phone? Can you help them do it in English, with appropriate language and pragmatic competence? How about the young learners talking about cartoons? Can they explain the plot, the characters or the appeal by involving you in a real conversation?
“What about the syllabus?” you might say.
Can you postpone that item? Work it in? Abandon it? I think we need to remember that syllabi are guides not commandments. And if we make things a bit closer to learners real lives they might want to work through that syllabus a bit more.