"[Sigur Ros] front man Jon Birgisson usually sings in one of two languages: Icelandic or 'Hopelandic,' a gibberish he made up that lacks vocabulary and grammar. It's unclear if any of these songs are in Hopelandic, since I don't speak Icelandic; it's all a bit nonsensical to my ear."
In the mood for nonsense? Check out "Hvarf/Heim."