How do actors?
The answer is Voice couching. If the actor doesn't already have an accent in the bag from their training or
previous work, there will be a dialect coach hired by the producers to assist, and they'll be present
through the rehearsal process. But a professional coach is not necessary. There are a lot of books with audio which help to develop their accent. Training accent without a coach They listen & do the exercises. There are
explanations on phonemes, vowel, & phrasing
pronunciation, which were repeated several
times for you to say and match to the recording. Also there are dialogues by natural speakers,
to listen to and practice mimicking. It’s as well
effective as to train accent with a couch.