“They talk over me and each other”

Very little of this is defiance. In most rooms the exact moment when talk has to stop has never been defined, so each student judges it for themselves, and one more sentence to a friend never feels like the problem. Your own habits feed it without meaning to. Every time you speak into noise, you teach the room that lessons carry on over talk. Every time you raise your voice to compete, the class adjusts to the new baseline, and next week you are competing with that.

The pattern holds because pushing on feels faster than stopping. Waiting for full silence looks like lost time when there is a lesson to get through, so you press ahead, though everything said into the hum has to be said twice. Nobody enjoys a stand-off over a murmur, so the murmur stays. Breaking it means separating your voice from the noise, and the techniques below do that in two broad ways: some give the class one clear, rehearsed signal that talk stops now, and some change how you use your voice and your attention so that you only ever speak into quiet.