Communicate via written notes - although native speakers?
According to this Washington Post article, the film Trainspotting, which is set in Edinburgh, had to have some of its dialogue redubbed with weaker accents for the benefit of American audiences (subtitles having been ruled out).
I once visited Edinburgh, and was unable to understand many of the locals. (I'm a native English speaker from Boston.)
As a speaker of (I suppose) mid-Atlantic U.S. English, I once had a non-conversation with a New Yorker...