In August, 1926, University of Nebraska professor Louise Pound sat down with a reporter and made a prediction. Eight slang words, she said, had already become common enough to stick permanently. Movies and radio were carrying American slang everywhere, faster than anyone could stop it, and these eight were proof.

Her list: kid, boost, bust, broke, jazz, jitney, buttinski, and flivver. Here's how six of those actually held up, and how they were used straight from papers printed that same year.
Kid
A reader that spring wrote in with a genuinely puzzled question: why do people call their children "kids"? The paper's answer treated it as if it needed defending. "'Kids' is a slang expression," the columnist explained, tracing it back to the literal meaning of the word, a young goat.

The Culver Citizen, April 14, 1926
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A hundred years later, it stopped needing an explanation so long ago that most people would be surprised to learn it ever did.
Broke
A Bridgeport bank ran an ad built entirely around the word, using it exactly the way anyone would today. "In all slang there is no more expressive word than 'Broke,'" the ad read, going on to call it one of the most pitiful conditions in everyday life, before pitching a savings account as the cure.

Bridgeport Telegram, March 10, 1926
Jazz
This is the one Pound most clearly meant as a compliment to American ingenuity, and it's also the word that had the most fun in 1926 newspapers. The British editor of the Encyclopedia Britannica had to publicly deny he'd "jazz up" the reference work while revising it for American readers.

Palladium-Item, April 23, 1926
Even better, a Cincinnati columnist got there first with the joke that actually predicts the future. An Amherst professor had said, "We must jazz up learning." The columnist's response: "In a year or so some folk will be demanding that we jazz up jazz."

A hundred years later, that's more or less exactly what happened. The word survived. Both as a verb to ‘liven up’, and also as the proper noun to explain terrible music (sorry Jazz fans).
Jitney
In Detroit, a jitney driver stopped to pick up two passengers, and police seized his car on the spot for obstructing traffic. He refused to drive it to the pound himself, so officers had it towed away while he stood and watched. The crowd's sympathies, the paper noted, were entirely with the driver.

Detroit Free Press, July 9, 1926
The word meant a shared cab or small bus. Unless you're old enough to remember it firsthand, there's a good chance you've never heard it used that way in your life.
Buttinski
This one shows up in the funny pages rather than the news. In a 1926 comic strip called Clarence, a man gets hit with a rock mid-argument and shouts, "All right, have it yourself, old buttinski," at the man who threw it.

It meant someone who couldn't stop butting into other people's business. Common enough to land as a punchline in a national comic strip. Rare enough now that most people would guess it's a typo.
Flivver
Kansas City reported on a full blown craze of teenagers and tourists painting jokes and slogans onto the sides of their beat up Model Ts, "flivver tattooing" as the paper called it. Lines like "Don't Laugh, Girls, How Would You Look Without Paint?" covered cars all over the city.

Kansas City Journal, July 18, 1926
Flivver meant a cheap car, and sometimes run-down car. The slang term didn't survive. The exact idea it described did, we just quietly swapped it out for “beater” sometime in the decades since.
The Scorecard
Kid and broke are just English now, so ordinary they don't register as slang at all. Jazz survived by shifting either to a verb, or proper noun. Jitney, buttinski, and flivver are effectively extinct, alive only in old newspapers, great grandparents, and comic strips like these.
Pound had a theory about exactly this. Slang either disappears on its own or slips into the dictionary before anyone notices.
She just didn't know which of her own eight words would do which.
See you tomorrow. – Chris
Sources:
Salt Lake Telegram, August 29, 1926
Bridgeport Telegram, March 10, 1926
Palladium-Item, April 23, 1926
The Cincinnati Post, April 20, 1926
Detroit Free Press, July 9, 1926
West Bank Herald, March 4, 1926
Kansas City Journal, July 18, 1926
The Culver Citizen, April 14, 1926
