Quite a few years ago I saw a program about people who stammer or stutter. They used a earplug device that allows hearing but lets the user hear their own voice ( a bit like putting your fingers in yours ears and talking you can hear you own voice..)
These plugs are small and unnoticeable and most of all they work straight away. I would say the guy mentioned earlier who stuttered on the ground but had a perfect radio manner had a similar effect happen to him in the air as he would have had his headphones on.
Try it, it may just work or at least ask your GP to find out about it. GOOD LUCK