I would normally not share any of the details of my pretty awful wedding, but this one seems apposite.
For context, we paid for it all ourselves. My mother and MIL loathe each other with the heat of a thousand suns and appeared to be in some kind of competition as to who could behave the worst towards us in the run up to the event. MIL via some very heavy emotional blackmail involving a dying grandparent convinced H to change the entire venue and the form of the ceremony at very considerable expense after all was paid for, and the work of essentially reorganising the wedding fell to muggins here. Perhaps that will give an idea of what I mean when I say they behaved badly.
In the run up to the wedding, there was the usual discussion about speeches. The day was fairly formal (H insisted in a massive expensive affair, I had my heart set on something as low key, small and cheap as possible, since the previous wedding we booked several years previously, MIL insisted be cancelled or she would disown H as she "wasnt ready for him to marry"; thousands of pounds of deposits were lost and I was too ashamed to ever go and collect the wedding dress I had bought), and as a result I was told by H there would be the usual speeches.
I asked if I might have a minute of my own to thank some people he had told me he was not prepared to thank (my little flower girls, my aunt and my elderly widowed grandmother) and it was made clear to me that he had spoken to ILs and there would be no departure from the usual list. I accepted this.
On the day, just before my father was to make his expected speech, H introduced my FIL who then went on to make a fairly lengthy and regrettably slightly drunken speech about what a great guy H is and how great MIL is. This would probably have gone down better with the guests if FIL had said literally a word about me or even H's brother, the best man, who like me was not prepared for this turn of events.
The guests did not receive this well. My father was so put off by this happening that when he was finally given the microphone, he was not his usual fluent self which he regretted bitterly.
Friends and extended family stil, occasionally make jokes at my expense about the "speeches hijack" and also about the outfit MIL wore. (A black veil is not traditional attire for the mothers at Catholic weddings. It is also not traditional for the mother of the groom to bodily shove the bride aside off the chapel steps as the couple exit and yell to the guests "I WANT A PHOTO WITH MY SON" either. This I regret to say was not the nadir of the day, although my uncle has a snap of a falling bride and a shoving MIL that will probably show up on a clickbait site some day)
I am certain OP would not engage in behaviour of this type, but I offer this purely as a caution against offering impromptu speeches at weddings when the bride and or groom clearly do not expect one to be given. The guests notice, they laugh, many people are embarrassed.
