In an interview with Insider, Irish actor Domhnall Gleeson affably talks about the wide array of accents he’s portrayed in a number of films, explaining how he incorporates the sounds and mouth shapes. He also shares which of the accents he considers to be most difficult.
It’s funny, Southern American is definitely easier than a more general American or something from either coast. The southern thing I don’t know. I think because of the way that the sentences work and the open down of the tonality of it you can hear it you can, grab on to it… South African or Welsh like they’re the nightmare ones they’re the ones that you just like wake up sweating about having to do someday.