I turned on tv and a film "SoI married an axe murderer" was playing It was the wedding scene and my attention was caught by the Scottish kilts (the groom's parents were Scots) and the tune playing. The song I know to that air is "Is truagh nach d'rugadh dall mi"; you might be more familiar with the chorus

Fill ò rò fill ò rò fill ò rò hug eile,
Fill ò rò fill ò rò fill ò rò hug eile,
Air fal il ill ò agus hò rò hug eile,
Chan fhaigh mi cadal sàmhach, a ghràidh, 's gun thu rèidh rium.

See the rest at http://www.geocities.com/alltandubh/I/Is_Truagh.html

I don't think the words are suitable for a wedding. It is a love song, but a sad one.