As you see, there are lots of versions in Irish. The onw Brendy gives is to the same air as I've heard Cathal McConnell and Kevin Mitchell sing the English translation.
By the way, the Irish-language song has been discussed on other threads, if you want to do a search.
Someone said above that Sean Bán MacGrianna lived just a km from the O Dugáin & O Braonáin families whose children formed Clannad. Not quite that close, nore like a few miles.