Its your wedding so if you are worried about a speech then don't do one. I'd be shitting it in your position and would just not bother.
Thats what I did, I just asked my best man to include a couple of things and then let him get on with it. If your not good or don't like this sort of thing it's not worth the stress and panic of it all and it will leave you then just to enjoy the day which is how it should be. My best man was a nervous wreck for day's leading up the the wedding about giving a speech and I remember I Kept on telling him there was nothing to worry about