Most Scottish people are like that. I've met a shit ton of English people on holiday over the years, and I've referred to every one of them as either 'English' or 'cunt'.
"English, is that your sister, and does she have grass on the wicket?"
"Here, cunt, put this in the freezer before it melts."
"What is it?"
"Who fuckin cares, cunt, just put it in the fuckin freezer."
Only person from England I've ever met that completely understood my gutteral tongue was a scouse barmaid. I have no idea how she did it. Any other English person (or any other person from any other country in the world, for that matter) I've spoken to, I've had to do it slowly in order to get them to understand what I'm actually saying. Basically have to do my best impression of Gerard Butler, and no amount of scrubbing with scalding water can cleanse that feeling from my skin.
When I'm drunk then you can forget about it, though. I don't give a shit where you're from and I don't give a shit if you understand a word that comes out of my mouth. Just put this in the freezer and we're cool. Nod and be about your business. Fuck it. Leave me to it.
Actually, Irish folks are generally pretty good at understanding Scottish people. I was so grateful for that that I bought one of them a stripper in Magaluf four years ago (and I'm absolutely serious about that. He sprung forth on her hair. And I'm absolutely serious about that as well).