S.M.
I stutter. I started to develop a stutter when i was about 3 1/2 or 4. A stutter can be caused by different things. My advice is to relax, she can pick up on you freaking out and it can make her stutter worst, and get her evaluated by a speech therapist. In the mean time, don't finish her words, that will just her her aggravated. If she gets stuck, stop her, tell her to relax and take a deep breath and start over. She will be ok, I promise!