I have diagnosed ADHD-PI (Predominately inattentive) and sometimes I wonder if it negatively affects my speech. I'm prescribed Vyvanse and I've noticed I actually want to talk to people when I'm on it. That confidence then turns into me stuttering less but sometimes it make it worse because it is an amphetamine so it's like having too much caffeine. I rarely take the Vyvanse because of the side effects, though. I'll feel great for about 4 hours but then my mood/energy crashes once it wears off. I just decided it wasn't worth it.