Just don't accept it. You're the adult and you have the right to tell her that speaking that way is inappropriate and you won't stand for it.[?QUOTE]
...emphasize consequences right now. We tell them they make their own path, but, there are good consequences and bad consequences for each of their decisions.
Lots of good advice here. We are going through this with 8yr old DS. He has a mouth that won't quit. (I just don't know where he gets that

). If he back talks or is disrespectful, he is immediately punished. I send him to his room for 10 minutes, when he sighs loudly at his punishment, I add five more minutes, then he starts "but..." +5, "no body understands..." +5 more minutes. It is not unusual for him to rack up 30-40 minutes. That will keep his mouth under control for a couple of weeks. He can't stand it when all the neighbor kids & his brother are outside playing & he's in his room because of his mouth. Oh well. He made his choices.
We are also having this problem at school - not with his regular teachers but specials & room monitors. I made him write an apology to the car rider room monitor for backtalking her. (She was extremely appreciative.) He now has a chart to be checked each day by each of his teachers indicating how his behavior (including his mouth) was. The options are "needs improvement/incident(s) occurred"; "acceptable" & "examplary". He runs the range. I left a voice mail for each of the teachers explaining that I am concerned about his mouth & his ability to control it. I also requested that they let me know the details of anything incidents or "needs improvement". He tends to have more trouble in the less structured situations. HIs homeroom teacher thanked me for implementing this "so late in the year". The closer the kids get to the end of the year, the more the behavior deteriorates. BTW - he has come home 3 of the 4 days with an exemplary from 1 of the teachers. Yesterday was the 1st "needs improvement" for his mouth since we started. (He & another kid had a disagreement on the playground & both resorted to name-calling.)