Maybe it's more specific... like a person from the "southern" USA meeting someone from Wales? They'd have quite a hard time understanding each other.
Some English dialects/accents are historically associated with lower-class people, or people perceived to be stupider/lazier/etc. Which creates all sorts of impressions on another person from the instant you open your mouth.
Many southern US accents have these kinds of connotations, for example, to such an extent that A) a lot of people won't take you seriously if you have such an accent and B) I'm glad mine got drilled out of me as a side effect of correcting for a lisp when I was a child.
I have also had severe difficulty understanding some of my wife's family, who are from Maine.
And now I work with many people from the UK. I tend to find that if the person is from the south, I have few problems understanding them. The further north someone is from, the more difficulty I have with them. Some of my Scottish coworkers are, for me, almost impossible to understand.