Many wedding receptions include speeches by the best man, by parents, and by others. But not all wedding receptions have them, perhaps as there are other ways to relate to guests in the general process of mixing during the cocktail reception and after. One couple ordered an empty chair to be added to each dining table so that the bride and groon could visit each table for a while.
I come from a formal background and think that speeches add richness, entertainment, and information about the couple. They give a kind of historic value or feeling to the occasion. I think a welcoming speech by the father of the bride when guests first sit down is a nice idea, accompanied by raising a glass of champagne. I think that certain persons need to be prompted ahead of time to give a speech.
What might the speech be about. Suggestions are: funny stories about the bride or groom, how they met, what characteristics of the bride or groom stand out for a happy marriage, how the bride or groom have been a great friend for years and would make a wonderful partner.
Not everyone is good at making a speech or thinking of an idea. But a speech doesn't have to be long. One can find speeches and toasts on the internet, and a reference perhaps to a Gaelic saying that seems appropriate might be good. One can just say something like "I'd like to raise a toast to John and Mary and wish them all the happiness in the world."
Everyone knows it takes a little courage sometimes to get up and speak before an audience, so even brief well-wishes are appreciated. Speeches are of interests to all the guests and give a feeling of being part of a supporting group and historic family event. Sam Milliken.