"It's all Gaelic to me."
 

I think it's a translation of a Gaelic phrase, Gail, relating to the male practice of wearing a kilt while attempting various kinds of Scottish country dancing.

In fact I have never known a Scotsman who didn't wear underpants with the kilt. The bare macbum is a myth. Or I think it is. Come on you Scots. Tell it like it is.