Hello Gerald,
I love all the replies you've got relating to public speaking - you've a lot to chew on, and perhaps you've been putting some of them into practice. Which ones, and how are they helping or not?
When are you first aware of the nerves gaining ascendancy before you give a talk? What, in your imagaination, is the worst that can happen, should you stutter, stumble, seize up or heaven help it 'run off'!!
I've not given many public talks - but when I do I practice EFT on myself - Emotional Freedom Technique. Have you heard of it? It is brilliant - and is a superb first aid tool for anyone. Simple to learn, simple to use, and totally - no, about 2% of people appear to have no benefits from it, but perhaps they're too special in the first place - and helpful for everyone. In a nutshell it helps to calm the body by sending messages to the brain, and lowering the adrenalin.
Look EFT up on the internet - I suggest having a session with an EFT therapist, who hopefully will guide you to use it in the best possible way.
Best wishes.
Susannah