I can't give advice, but I can share the frustration. My verbal brain is like an engine that has trouble starting. Once it's puttering away, I have the momentum to ride over blocks (or evade the words that might trigger a block), and just tough it out over elongations and repetitions – but SAYING THE FIRST WORD is the hard part. When I try to initiate a conversation but suffenly block, people stare at me and say either, "What?" or "Are you OK?" because everything about my face and body language says I'm about to say something to them. Actually, now that I think of it, hand gestures help me. I literally can't say "hi" to someone without accompanying it with an actual hand wave.