Why do my lips twitch when I'm very upset and trying to talk?

It makes me look like a moron. It seems involuntary although I don't know for sure. Why does this happen to me?Why do my lips twitch when I'm very upset and trying to talk?
When I was little if I got hit or yelled at and started to cry my lips would twitch while I tried to hold back tears.Why do my lips twitch when I'm very upset and trying to talk?
its probably just something you do when you get mad/upset. Everyone has something they do when they get mad/upset.
My eye twitches... It's a anxiey based reaction. You could be happy or mad. Everyone has something I think...

the bees