I'm from the other end of the spectrum.
I've also worked with a lot of migrant people that are still learning English and there's a lot of strange different accents with their use of language too, and then you get someone with a heavy Irish or Scottish accent and neither of them can understand each other. I acted as interpreter a lot.Though I must admit, I do get amused by hearing non-British Europeans who somehow manage to speak English with an American accent. Even those whose nations are so close to Britain. Interesting.
It also makes for confusing conversations sometimes too when you're talking to people in other countries because there's also some words that have different meaning to us than they do to others. Thongs for example, here that means footwear.