In any case, this reflection also leads me to the use of the mother tongue in teaching English. Whenever I am in a situation where I see that the students do not seem to understand my instructions. Or even after not responding to a simple sentence Did you understand ?. . . (of course not the younger ones) and are not able to at least nod yes or no. So I have various feelings, typically negative.
Or even after not responding to a simple sentence Did you understand?