Language evolves. The English we speak today isn't quite the same as the English of the King James Version, which was perfectly normal in 1611. And that form of English isn't the same as the English of 400 years earlier. For us, Old English is literally a foreign language, even though it is, as the name indicates, a form of English.
Just in my lifetime English - at least American English - has changed. I'm not talking about vocabulary, though there have been changes there (usually, as fads and variations of fads come and go, in the direction of more belligerent, angry English), but about pronunciation and enunciation.
One change has been in the flattening out of long vowels. The long E sound of steel/steal, feel, or real/reel has become a short I - still, fill, and rill. The long A sound of sale/sail, fail, and male has become a short E - sell, fell, and Mel (this last has created some amusement for me - there's a late night radio commercial for a product which the announcer calls "Ageless Mel").
Consonants have also changed. The T following an N has gained dramatically more emphasis than it used to have. Instead of printer and hunter, people are saying prinTer and hunTer (the same is true of the root words, print and hunt). People are pronouncing a D as though it's a T - melted, furled, and printed have become meltet, furlet, and printet (actually the last has become prinTet). And the letter S has really changed. Sometimes people pronounce it as though they're imitating a snake - caress and abscess become caress and abssssssscesssssss - and sometimes they emphasize the S so much that it sounds like a T. For a while there was another late night radio commercial (I work nights, so I hear these things) which advertised a brand of insoles, except the woman reading the copy pronounced the word intsolts.
In 1976 Anne Rice published this exchange:
"We were living in Louisiana then. We'd received a land grant and settled two indigo plantations on the Mississippi very near New Orleans..."
"Ah, that's the accent..." the boy said softly.
For a moment the vampire stared blankly. "I have an accent?" He began to laugh.
And the boy, flustered, answered quickly. "I noticed it in the bar when I asked you what you did for a living. It's just a slight sharpness to the consonants, that's all. I never guessed it was French." (Interview With the Vampire)
Today that exchange is nearly meaningless, and whatever meaning it retains is backwards. In today's American English "a slight sharpness to the consonants" would be the mark of someone who's trained himself almost completely out of the current American accent (though of course Americans only have an accent to non-Americans; to the British queen, for instance, she doesn't have an accent but I do, which is exactly the opposite of how I view it). Sharpness to the consonants - and changes in the pronunciations of the vowels - is how most Americans seem to speak these days.
My characters do not speak that way. They speak as I do, which is the way most Americans, regardless of where they came from, habitually spoke as recently as 20 years ago. I still talk the way everyone did when I was 10, when I was 20, when I was 30...for that matter when I was 40, for although the changes began perhaps 20 years ago, they didn't become pervasive until the past 10 years or so, and possibly an even shorter time (I didn't make it a point to note at the time when the current way of speaking first became current). If you "hear" any of my characters really emphasizing the T in "hunt," or hissing the S in "kiss," or talking about "a still sell" when he means a "steel sale," then you're "hearing" them incorrectly. You need to assume that, unless the story specifically says so, all my characters speak as Joan Lunden did when she was on Good Morning America (and probably still does speak - she's a California native as I am, and roughly of my generation).
Now there are characters in my stories with accents - Yirmeyah Hudson, for instance, who even by Texas standards has a strong accent, or Albuquerque Moreno who when she's engaged in casual conversation sounds like any other black woman (as a side note, it's only in the United States that blacks have a distinct way of speaking; elsewhere in the white world - England, for instance - they sound like everyone else). But thus far I've not had any characters who talk in the self-consciously "trendy" way that has become ubiquitous these days. And unless Darvin Carpenter talks to someone who does, such a person probably won't appear in my fiction. :)