She wasnt a actually mute...
From the way the film was marketed and from the name of the film i assumed she choose NEVER to speak and it describes her as being a mute and yet she chooses to answer questions and even talk normally... i dont think they should have described her as being a selective mute she was quiet but not mute.
apart from that it was a great movie and Kristen Stewart's acting was very good.
"Someone has to die in order that the rest of us should value life more. It's contrast."