And I know it's a pretty limited repertoire in each, but my Japanese website does include the first verses of four Christmas carols in (romanized) Japanese: The First Noel, In dulci jubilo, Lo how a rose, and This Endris Nyght — and my online hymnal, in addition to 125 hymns in Esperanto and more than a dozen in English, has a few in Dakota (1) French (1) Hawaiian (1) Spanish (1) Huron (1) Yiddish (1) Latin (3) Dutch (1) Scottish Gaelic (1) Swedish (2) and Vietnamese (1) (scroll down from the English ones to find the other languages). Some of these are of folk interest one way or another (e.g. the Vietnamese item is the first stanza of Away in a Manger, set to Flow Gently Sweet Afton, which I think nowadays qualifies as a folk tune)... and I know a few songs in other languages, too, e.g. Russian, which I might be able to help with if the right question came up.

Liland