I was told by a wise old Irish lady that having a musical ear does help with imitating accents, and after spending any time in her company, I found myself speaking with a definite Irish lilt. Not that I could keep it up for a song, though, without sounding as though taking the Mick. Unless I had learnt said song from an Irish person's singing. But it still wouldn't Feel right.
The other day I caught a u.s. actor playing a Brit on TV, exclaiming "but I'm Briddish!" Ha! Yanks incapable of using letter T. Like us Brits with R. Dead giveaway on both sides.