Problem language
Don’t get broken –
Instead say: Your weight was off balance; put your weight on the break side leg; keep your knees bent; he likes to throw high on his arounds; he likes to throw low I/Os; watch his hips; he never throws the first fake; etc.
Don’t get beat deep –
Instead say: position your body to force him underneath; let him have the underneath; when he finishes an underneath cut, stay on his outside shoulder; stay between your man and the disc, even if he is way out on the break side; always reposition when you have the chance, ideally you want to triangulate (see your man and the disc simultaneously);
Stop getting beat up line –
Instead say: position your body to force him behind the disc; give him the around but make sure you are there to put on a sick mark; don’t pay attention to fakes and jukes, just know that you must stop the up line; fight for the ground you are defending, don’t chase your man; pray they try to squeeze the disc up line so you can layout D your man;
Catch the disc! –
Instead say: focus on the catch before your next move; watch the disc all the way into your hands; get it back on d/efense;
Some friendly heckles instead of swear words:
-Somebody get that guy a library card, he needs to learn to read
-You look sexy when you drop the disc/get burned/etc
you get the picture

The key is this: everybody wants to win, everybody wants to do their best, and everyone is certainly working hard. We are a team, and we have to support and build each other up - attacking each other, even the weakest of the team members is going to kill us. If you are going to say something, take the time so that you can say something constructive rather than destructive.