I had the same as you (I think) and I have been speaking completely effortlessly and fluently for the past 4-5 days after a simple ''tweak'', I noticed that I engaged my abdominal muscles while speaking and by engaging those muscles my larynx became ''stuck'' as well and made me unable to say the word while I could say it perfectly a few seconds later. Anyways if you want to talk further I would be happy to see if I can help you in any way, send me a PM if you're interested. PS: Are you familiar with William Parry's work?