Dialects are not the same as accents.
An accent is a way of speaking that reveals one’s place of origin.
Dialects have distinctive vocabulary, pronunciation, intonation and grammar.
Native speakers usually have no difficulty understanding English spoken with a regional accent, but they may find it difficult to understand a thick regional or ethnic dialect.
People talk about “mild” accents and “thick” accents. A mild accent is pleasant to listen to. English spoken with a “thick” accent can be difficult to understand.
Accents add interest to standard English, but—people being people—the speakers of one type of English often stereotype those who speak with a different accent.
Accent and dialect as class markers
Script writers make use of regional accents to convey character types. For example, gangsters often have New York or Chicago accents. Wealthy and/or educated characters in films often speak with New England or British accents.
Television interviewer Charlie Rose, born in North Carolina, retains a soft Southern accent that has not hindered his career.
Stephen Colbert, on the other hand, born in South Carolina, felt that a Southern accent would hold him back professionally. He has worked and studied to eliminate every trace of regional accent in the speech he uses publicly.
“At a very young age,” Colbert said in an interview, “I decided I was not going to have a southern accent. [On] TV, if you wanted to use a shorthand that someone was stupid, you gave the character a southern accent. And that’s not true. Southern people are not stupid. But I didn’t want to seem stupid. I wanted to seem smart. And so I thought, ‘Well, you can’t tell where newsmen are from.”
Colbert decided he would speak with an anonymous “newsman” accent.
In making career choices, don’t forget to think about the form of English best suited to the work you want to do.