Take the following as truth: In the matter of pronunciations of BrEng names, it is an old-fashioned fantasy of Americans that Brits go round saying POM-frit for Pontefract : most Brits that I have heard give the name a spelling pronunciation these days; and so with many of the old shibboleths.
Then the following statement: "Americans perfectly understand British accents." is true, false, or inconclusive?
Answer: False