Regaining an accent

A recent post on accents and a tv show made me wonder if someone can regain an accent. I was watching Syfy’s “Sanctuary” with Amanda Tapping, whose character is a long-lived English scientist, accent and all. However, Amanda Tapping was born and lived in England until she was 3 years old, right around when most people speech is undergoing development, to Canada. In most of her shows, such as Stargate SG-1, I don’t detect an accent. However, is it possible the accent she affects on her current show would have been hers if she had stayed in England? Would a person born in Mississippi moved to Boston at 5 and then moved back home regain his “original voice”?

I’m guessing that one can get back to an original accent, just based on personal experience.

My college friends in Virginia used to remark about my “regaining” my Long Island accent when talking on the phone to friends from home.