How to disable or slow down key repeat function


The repeat function(and delay time) is much quicker on the delete button than the others. Can I change the delay or even disable the repeat function on the delete button? Every time I hit a wrong button I accidently erase too many characters and totally mess up the word prediction in T-9. T-9 is really good for me since it allows me to use fewer keystrokes when typing.
My coordination is really bad due to a neurological disability.
I also wonder if there is any way to speed up the quality level and learning rate of the smart and personal dictionaries, especially with T-9. Does T-9 use different dictionaries and is it possible to get the word prediction to suggest the next word before you start typing, based on the previous word?

/CG Fresk