Being a Weegie anywhere outside of Glasgow, no one understands a word you say!
I once had the misfortune of working with a UK unit in a field exercise, in regard to their terrible food and the fact nobody could understand anyone else. Most of my soldiers were from the Southern states and most of the Brit soldiers were from the North and Scotland. Being from the southern US, I could speak/understand that and being somewhat cultured could understand most of what the UK soldiers said. So, I wound up being pulled off my observer status for the exercise and mostly used as an
interpreter between the NCOs and officers of both sides.
That said, there were plenty of times when vernacular was used by the Commonwealth troops that I had say, "I'm sorry, I couldn't understand, what do say?"
I'll never forget the UK Major who said in front of my troops, "Soddin' 'ell, Leftenant, 'ow else do oi say it?" All my Battalion NCOs were looking at each other and I'm sure I heard one mumble, "Uh, he
is speaking English, isn't he?"
Another said, "Man, I feel sorry for the Eltee, he had an easier time with that German outfit we dealt with last summer!"
It's true, I did.