No way. No words of disrespect at all. Not stupid, not shutup, not I hate you... I don't even let my kids talk to each other in a rude or nasty way to each other let alone to any adult. It's not on. We don't talk to them that way so they are not allowed either. If you want your kids to respect you, you need to show them you won't tolerate disrespect. Doesn't mean you demand respect (I don't believe in that either) but allowing certain behaviour IMO is like saying "You can treat me like crap". It's our job to teach them right from wrong and this is a BIG one that I am against.