D.C.
I have a 3 1/2 year old and a 7 year old, both girls. One thing I try to do is use the word "we". Like "we don't talk that way to each other" or if you are unhappy we use words like "I don't like that" or "no thank you". My oldest daughter tells me quite often "this is the worst day ever!"
I also suggest other ways for her to answer if she is upset about something. The key is to stay calm and keep that low but firm voice.
Sometimes I just stand there and when they are done yelling I say, "ok sorry you feel that way, now please do as I ask." Then I walk away into another room. I think leaving the argument tells them silently that the decision has been made. This works on both my kids, its worth a try. I do try to hear them out though and listen to what they are saying.
The other key is remember positive reinforcement, when she does express herself in an appropriate manner, praise her for it. Whether or not she agrees with you on the argument.