I can't comment on the language abilities of those mentioned in the article as I just don't know whether it's true or not. Certainly the resurgence of gaeilge in the North has been down to the republicans, the language was taught in the prisons by and to other prisoners.
An old mate of mine from my Paris days who is ex-PIRA and did six years in the Kesh is an avid Irish speaker (now living in Strabane). His partner is from the North of England and started learning a bit when they moved to Strabane with their two daughters. When I was last there I was chatting away as gaeilge to my friend and his eldest daughter who know speaks Irish with a Tyrone accent as the daughters go to the local gaeilscoil. It was delightful!
I have mixed views about what could be perceived as cultural appropriation in the use of gaeilge by the republican movement but the language is a part of our cultural identity.
My Grandfather was a Corporal in the RDF 6 Co. and fought on the Somme. My late father suffered a lot of bullying as a child growing up in Dublin because of it, so he translated his family name which was passed on to myself and my brother.
During my time living in London during the Troubles when I was travelling back and forth via the wonderful boat and train experience, every single time I'd be pulled over and asked for ID. Every. Single. Fucking. Time. it was "What's your name in English Sir?" My blood would boil. I'd have to patiently explain to the Branch Officer that this was the only form of my name that I ever used. It would lead to a stand off where they would re-consult "The Big Blue Book" again and again to see if my name was in it. (Pre-computers, TBBB was the ledger that contained the list of names and aliases of those known to be involved in the Troubles.)
My brother moved to the UK in the early 80s to start his journalism career but decided to use the English form of our family name which he still uses today. Back then there was no way would he have been employed in England with a name as gaeilge. It still amazes me when I see Irish names as gaeilge on the credits on UK TV programmes and films.
Again when I worked in London I had a Scottish boss in a Design Company who would all me Shamus, some customers in a bar I worked in in Putney Heath would also call me Shamus as they were too fucking ignorant to learn how to pronounce my real name properly. FFS! It's only two syllables, how hard can it be!??!
Living in France no French person ever had a problem with my name apart from pronouncing it from the written form they couldn't however get their heads around the use of all the fada's. Once they heard me say it once they could pronounce it.
Irish people (especially some Dubliners) still mispronounce my name by using the "O" sound rather than the correct "Uh" sound.
Make of the above what you will.