What accent do you speak? Do you even think of your particular accent as you engage in day-to-day conversations?
We all have accents. And no, in the United States, there's no one accepted accent: we're too big a country, and we have too many regional differences for any one way of speaking to prevail. Even if people from one region mock the accent of those from another, no one accent holds sway over the others (though the bland newscaster accent seems to be the one many people, for some reason, aspire to).
Even within states, accents vary: upstate New York is different from Long Island, and different from Manhattan. New Jersey north is different from New Jersey south, and different from nearby Philadelphia. Boston and Maine might have similarities, but the accents are recognizably different.
And in the South, a Mississippi accent is quite different from an Arkansas one, and different still from Texas. Along the West Coast of the U.S., Californian accents are different from those of Oregon to the north and Washington even farther north, and just as you go over the border to Canada, the accent becomes something different again.
And while there's no accepted accent, the way you speak can mean certain things to certain listeners. You may come off as pushy, or as a rube, or as a nerd or a snob. Just by speaking the way you speak.
In Britain, accent means a lot: class, upbringing, economic status. An interesting video in which a speech expert (and accent coach) gives an audio tour of the different accents in the British Isles has been making the rounds.
When you write, of course, you don't have an accent, though certain regionalisms might creep into your prose. But how you frame your thoughts, how you approach your listener, is accent-free. But how you write to your audience is something else entirely; if you're an expert, you need to frame your expertise in a way that allows you to explain yourself without jargon. You might not have an accent when you write, but you should always address your reader as if he doesn't quite understand what you're going to say.
The paleontologist Neil H. Shubin does. As he explains in a conversation with the New York Times:
When I'm writing, my dad is my target audience. Whenever I hit a tricky scientific concept, I think, 'How would I communicate this to him?' This is why my books are written, intentionally, without jargon, which can lead to some gyrations because jargon does have precision.
Whatever the accent, clarity is the goal.