If most of the guests are 'Folkie' types you will be fine so long as you keep it simple. If half of them don't have a clue you need to be prepared for lots of talking over the calling as people are there to enjoy themselves and for a good chunk of the population that doesn't include ceilidh, and you can't tell the audience off at a wedding like you can at a dance club! If our caller is having trouble getting people on to the dance floor we sometimes sing a lively song (Tell me Ma or something similar) or play some lively tunes, usually Irish style, and up the volume just a little bit. This usually gets their attention. Weddings can be hard work as you are always trying to please the person who booked you and the majority of the guests and the two don't always tie up.