From Dickens's cockneys to Salinger's phonies, from Kerouac's beatniks to Cheech and Chong's freaks, and on to hip hop's homies, dialect has always been used as a way for generations to distinguish themselves.
People, generally, suck.
I kind of dislike 'For Whom the Bell Tolls,' but most of Hemingway in general, mainly because his stylistic shenanigans ruined so many young writers of my generation who tried to imitate him. I think, for his time, he moved fiction to a different level stylistically, or at least added to the dialogue, but in our time, he's annoying.
When I teach seminars, I tell people, 'Your stuff has to look like something that's out there, because otherwise nobody will take a chance on you.'
I thought I was going to be a horror story writer. My influences were horror writers, like Rich Matheson, Ray Bradbury and Bram Stoker.
All of the trickster, rascal characters that I write have the voice I aspire to. In real life, you can't be that obnoxious and get away with it.