It depends on the individual. Some stutterer don't stutter at all when they speak out loud to themselves, or to their dog. I tend to stutter lot less when I speak to myself, but I do stutter. I think it is definitely beneficial to speak out loud with yourself, esp. if you're not used to speaking at all. But my tip for you is to start going out to stores and talking to the cashier, employees, and trying to stutter voluntarily with them. This approach helped me immensely gain my confidence back. Look them in the eye, speak in a firm/loud tone, and 'try' to stutter as much as you can, as confidently as you can. First few attempts are the hardest, but the more you start doing it, the more you'll start feeling confident speaking to others, with or without stutter.