It is very common for children around that age to develop a stutter as they speak. Your child is not in any danger from the stutter, and it is nothing for them to be ashamed of. Statistically, they will probably grow out of it. All's well that ends well :) If the stutter persists as they get middle-elementary school age, your child will still be fine, but consider finding them a speech therapist that can help them understand the impediment that they live with. Your local school system (at least in the United States) can usually provide one for them, and therapy can be found outside of a schooling context as well. A local university might operate a clinic, for example.