I agree that accents are shaped by environment, but as a black person, it's fairly easy to pick out when I'm talking to a black person even when I can't see the

I agree that accents are shaped by environment, but as a black person, it's fairly easy to pick out when I'm talking to a black person even when I can't see them (i.e. by phone), just as I could detect a Spanish accent, Indian accent, etc. That being said, a lot of black people I know change their accents depending on their environment -- work-related, vs. passing time with friends. They (we) are often cognizant of the fact that you need to speak crisp, clear English, as not to be thought stupid.