There is also a documentary (they highlight on the blog and interviews) that focuses on Irish language in Ireland.  Since Navan sings in the languages of Ireland, Scotland, Wales, Brittany, Cornwall and the Isle of Man it is an issue for them.  Sort of an interesting presentation, although its lacking subtitles is a bit of a barrier, but it is clear his effort to speak only Irish in Ireland ended in problems. Here's the beginning and the rest is on the website of Manchán Magan--the documentary is called “No Béarla”