Okay, so the intent of this piece is not to help fictioneers but to lament a trend in spoken English.
It’s by Clark Whelton, who as a speech writer for NY City mayors Ed Koch and Rudy Giuliani (!) screened interns over a number of years.
Around 1985, he noticed that college grads began to sound increasingly inarticulate.
I agree, this is lamentable. (And what does this say about the future market for fiction? Whoa, let’s not go there . . .)
But if we set aside our angst for a sec, we have some great tips here in how to write dialogue when the speaker is a teen/young adult.
There is, of course, the ubiquity of the word “like,” and the interrogative rise at the end of declarative sentences (personally, I wouldn’t end declaratives with question marks too often in my fiction; its the sort of thing that should be used sparingly; but if used sparingly is a great tool for conveying that speech pattern in a character).
Another that is pretty well known — to the point of being widely parodied — is “Playbacks, in which a speaker re-creates past events by narrating both sides of a conversation.” Example: “So I’m like, ‘Want to, like, see a movie?’ And he goes, ‘No way.’ And I go . . .”
Then there’s the verbal tic Whelton calls “Double-clutching.” The example he gives: “What I said was, I said . . .”
He also gives some examples from Catcher in the Rye:
All the way back in 1951, Holden Caulfield spoke proto-Vagueness (“I sort of landed on my side . . . my arm sort of hurt”), complete with double-clutching (“Finally, what I decided I’d do, I decided I’d . . .”) and demonstrative adjectives used as indefinite articles (“I felt sort of hungry so I went in this drugstore . . .”).
Pretty nice little tutorial there, don’t you think?
The trick will be to write this kind of dialogue without making your character sound like a nitwit, or worse yet annoying your readers. LOL
Related: The Decline of the Imperative.