Oh yeah ... I'm frequently saying "shhhhh" and by night time I've been known to shout "SHUSH" which seems pointless since children learn more from what we do, than what we say

Most of the time he's ok now though, we told him that he can shout outside, but not inside. It's only when he gets excited he forgets and shouts these days.

It does your head in doesn't it. It'll pass