I'm no expert but I think a big issue with listening to these American-Brit pairings are that the many American narrators don't have good accent/dialect training.
I am pretty sure that Vanessa Edwins botched 'twat,' which prompts me to link to Daniel Sloss...
https://www.youtube.com/watch?v=lAYtv... (4:40ish but the rest of it making fun of Americans & American 'Greatness' is well worth it too)