Disciplining Teenagers: Stop Back Talk
Sit down and talk to your daughter calmly at a time when she's speaking in a way you DO appreciate and tell her how much you like to be talked to like that and how close and connected you feel to her when she speaks like that. Let her know that the sassy way of talking does not feel good and really isn't an acceptable way to speak to you.
Tell her you know at times she'll be under stress and may react that way and you'd like to be able to remind her at those times that her tone of voice needs to change. Ask her for a cue or a prompt you could give her, such as, "Could you say that in a gentler way so I could react well?" You can't expect her to be nice all the time but if one reminder does the trick and she can change her tone of voice, you're doing well. Another option is to ask her if she needs a short time-out to calm herself down so she can tell you what she's upset about in words, instead of taking out her emotions on you with an unacceptable tone of voice.