Notes

Figure out what's behind it. Sometimes an obnoxious attitude is a reaction to stress, disappointment, or even too little sleep. Middle schoolers are trying to prove themselves academically and socially, and it can be a challenge to keep negativity and cynicism at bay when they're emotionally depleted. If your child had a fight with a friend or is doing poorly in school, a flippant "so-what" tone may conceal fear or anxiety. If she hears you or a spouse speak rudely to others, she'll copy that behavior.
Target one attitude at a time. Do you bristle at his fresh mouth or sense of entitlement? Are you most offended by her barely-under-the-breath remarks or the way she rolls her eyes when you speak? While there may be several things you wish would disappear instantly, focus on one at a time.
Nurture the attitude you want to see. Once you've targeted the offensive attitude, zero in on what you'd like to see instead. For instance, an insensitive child needs to be caring and empathic; the non-compliant child can learn to be respectful and dependable; the demanding child should be considerate.
Stay cool. Like the schoolyard bully who hones in on the one kid he knows will cry, your child wants to see that he's ticking you off — and he's probably quite good at it. That's why you need to plan ahead. "Pretend you're on Oprah," says Borba. "Memorize a short script so you can clearly but calmly respond to a child's hostility in the heat of the moment." Never lash back ("Don't you dare speak to me that way, young lady!"); she'll focus on your anger, not what you're saying, and before you know it you'll be embroiled in a power struggle.
Draw your line in the sand. During a peaceful moment, patiently point out the attitudes you're concerned about. Make it clear that, while you understand her feelings and opinions, you won't tolerate her response. You could say, "I know you think I'm not being fair, but I won't be spoken to like that." Or, "That may be the way you talk to your friends, but it's never okay with me." Give her another chance to respond in a kinder, gentler way: "If you'd like me to help you, ask politely," or "You call me clueless, and that hurts my feelings. Can you say it another way?"
Follow through with consequences. If your child has slipped into the habit of being disrespectful, he really may not be aware of it or, in the heat of the moment, realize how wounding his words are. Still, Borba advises that you "flat out refuse to respond until he does." If it continues, ground him or take away privileges: no cell phone or X-Box, an early curfew, missing an important social event.
Notice the good times. When the infuriating comments cease, let your child know you're proud of her. And hang in there: by the age of 14 or 15, the nice kid you used to know will come back.