Interesting clip here: https://www.youtube.com/watch?v=iM5qA_luSI8
I would do a transcription on request for any small section of these, or any other video, but I admit I was unable to catch somethings here and there. Isn't that lilting genius, by the way.

I love it.

This is very interesting. I don't know the meaning of every word he uses, but I can hear and recognize them.

I do wonder if this is the same for people who have mostly developed their ear listening to school Irish. Can they recognize the words when heard? Could they repeat what he has said?

I am currently working with a few students who have learned incorrect English pronunciation first. It is a very interested process undoing that. It is like their ears are trained wrong not just their mouths. Not only do they need to have their output corrected, they need help fixing their listening. For lack of a better word, it seems like a radio that needs to be tuned into the right frequency before it can pick up the message. They can understand incomprehensible (L1 influenced) English but not native English.