By "disabled section" do you mean when they call for people who require assistance to board to come forward? (I don't recall seeing a disabled section of the plane as in disabled seating before, and I fly a lot, but maybe some airlines do?) If you mean boarding, I don't know how strict they are about who qualifies, but if it's your first time flying (or maybe first time alone?) and it would really make you feel better you could go up then and have a note ready on your phone saying "I have a speech impairment and this is my first time flying alone" or something like that. The worst that will happen is they'll tell you to sit down and board with your assigned boarding group anyway. As others have said, you generally don't need to speak to board a plane - but I will add, that is true as long as you are not seated in an exit row. If you are, they will probably ask you to confirm that you are able and willing to assist in an emergency, which they do require verbally (I was once in line to board behind someone who was mumbling and not giving them a clear answer and they ended up moving her because she wouldn't give a clear "yes".) I'm not sure if a severe stutter disqualifies you from exit row requirements but maybe try and avoid it. If you need to ask for anything during the flight, I'm pretty sure typing your question/request/food order on your phone and showing it to the flight attendant will be totally fine even if you just board like normal. Between speech impairments and language barriers, I imagine that's not all that unusual.