As a note, I don't intend to buy off the mute thing.  At least, not for a long while, at least.  She'll lose the paranoia before the muteness, because the inability to speak is mouch more deep rooted.  Paranoia is because she's terrified of being caught, but the mute thing is from losing her innocence in just about the most horrible way.  After all, she was very young when she was captured and trained, and has killed and worse, always against her will and always unable to stop herself.