I have no advice. You mention "almost always the first word". Have you noticed in what situation that is? I mean, is it in answering a question (and, if so, to whom: a younger sibling, pre-k friends, an authoritative figure (an older sibling, teachers, store clerks, police, strangers, you the parent, &c); or when he is too excited to tell a story or just in general regardless of environment. In any case, might want to mention that when you get to see a therapist.