There are plenty of good reasons for having rehearsal dinners. It's an opportunity for parties from the groom and the bride to get to know each other. It is to break the ice before the big event.
However, many miss out on the opportunity to get people to give wedding speeches on rehearsal dinners. It is a common dilemma for the couples in selecting the people that would be giving wedding speeches or toast. Because having too many people speak will just bore the rest of the guests and will just take too long.
That is why it is important to have people speak in wedding rehearsal dinners. It gives the to-be-weds an opportunity to invite other people to speak their affection for the couples and honour them on this special occasion. This would include cousins, co-workers, schoolmates, and other people that normally would not be invited to speak during a wedding.
Having speeches during rehearsal dinners also warms people to the whole speech giving process. This can be especially important to those people actually speaking during the wedding day itself. The benefit of this should not be underestimated as it is definitely a big boost to people petrified in giving their wedding speeches on the wedding day. To see other people other people make it through their speeches despite their vulnerabilities brings tonnes of confidence to your main speech givers.
It would also be a good idea to invite those giving speeches on the actual wedding day to give a quick toast on wedding rehearsals. It gets them accustomed to standing in front of a crowd and realise that it is not such a bad idea after all.