It helps mine, but it hurts my brothers’. It was my college room mate who first noticed that I didn’t stutter as bad when I was stoned. I suspected it was the CBD but wasn’t sure until years later when I tried high CBD cannabis for the first time and my stutter got better. I bought some tincture and found it worked for me. My younger brother has the same kind of stutter as me, and he says that when he’s smoked it’s made his stutter worse, so YMMV.