The words and ideas you express are important, of course, but nearly as important is the way you sound when you express them. Indeed, there are still people in the world who will judge your accent before they even consider your words. You may even have your own biases.
There are a few distinct accents in the United States. People from the South are said to drawl, speaking slowly and stretching their vowels out. Some people find this accent reassuring; others think it sounds unintelligent. One accent from Southern California, with very rounded vowels, has been mocked in TV and movies as the dumbest accent in America. New York and Boston accents can sound decisive or rude, depending on the listener.
In England, accents have always been very important. Even these days, children with undesirable accents are sent to elocution lessons, where they are taught how to speak like the upper classes. Many studies show how people respond to accents. Scottish accents are seen as reassuring. People with accents from the Midlands of England are seen as untrustworthy and may suffer career discrimination as a result. People from Liverpool are thought to sound "unpleasant," while people from Ireland, apparently, sound "sexy."
In many countries, people with city accents may be seen as smarter, wealthier, and more accomplished than people who clearly sound like they are from the countryside.
Your accent, of course, reveals nothing but where you grew up—not your intelligence, not your trustworthiness, and not your value. Being able to use different accents in different situations may help people avoid prejudice, but it would be better for all of us to recognize our own irrational biases and fight against them.