The vocals for the singing are in Irish Gaelic. My previous Irish wife was fluent in Gaelic. The Irish government did (maybe still has) programs to promote speaking "Irish;" i.e. Irish Gaelic. In high school, she spend summers in the Dunnygaul part of Ireland living with native Gaelic speakers. The payoff was she took her school leaving exams in Gaelic and was given a priority assignment to a scholarship in college. There are still a few native Irish Gaelic speakers in Dunnygaul (the northwestern part of Ireland). There are no more Scottish native speakers of Scottish Gaelic, but there are still people who have kept that language alive...even here in Los Angeles, there are get-togethers for people keeping the language alive to come together and speak Scottish Gaelic.