Oh it's awful isn't it?

We just tell DS that "It's too loud, please use your inside voice. " if he doesn't stop I tell him, "that's too noisy, I'm not listening" then don't respond until he stops. If he talks I talk back but screaming gets no response.

Generally I don't like ignoring him, but any attention paid to the screaming made it 50 times worse. Every time. It took a while but he knows now that if I say it I mean it, and he stops within a minute or two.