Just because it's in a minority (preferably Celtic) language, doesn't make it the original version: the Jersey pages are a total red herring - most of the songs there have been translated into Jerriase very recently.

Or did Paul Simon really steal Comme un pont à travers d's ieaux troubliées and translate it into Bridge Over Troubled Water? There are songs there by the Beatles, Dylan, etc, etc. Good fun perhaps, but nothing there for the serious researcher.