So we had to learn a very specific midland, rural, quite thick accent, and it sounds completely different from a metropolitan, sort of Dublin Irish accent.
She also explained why Dornan, who is himself Irish, appears to speak with a not-particulary-good Irish accent in the film.
“How does Jamie Dornan, the only Irish person in the trailer manage to have the worst Irish accent of all of them?”
The accents used by Blunt and her co-stars (including Jamie Dornan and Christopher Walken) were even jokingly compared to a “hate crime”.