My dad is refusing to do a father of the bride speech

Hi all! I’ve had several conversations with my Dad about the wedding and the first thing he ever brings up is that fact that he is not doing a speech. I always reply saying that I really want him to and that he should. But again he always refuses. It’s difficult because my Dad is the absolute worst for sarcasm, I think in my life I can count on one hand the amount of times he actually has responded to a question (literally any question) with a serious answer. We are now 4 months to go, and I’m now growing concerned that he really is not planning on making a speech. I’ve tried to ask and I’m just getting nowhere! He just doesn’t seem to realise how special this is to me. I lost my mum about 18 months ago, a few months before I got engaged, and so input from him I feel is extra important now as I know that my mum won’t be there. Am I being silly to try to keep explaining to him how special it would be to me, or should I just accept the fact that he’s not going to do a speech?