> I think you see this play out in Ireland, actually: there seems to be more of an interest in the Irish language in Northern Ireland, where the Irish identify is seen as more under threat, than in the Republic, where it is safe.

You have this backwards. Ireland, both Ireland and Northern Ireland, have pockets of interest in the language and culture, but it really is true that the country, culture, and language that was Ireland pre-famine no longer exists. It was successfully and deliberately eradicated.