This is something I hadn't really ever thought about--it's been around all my life, of course, and I just take it for granted. I'll paraphrase and quote a bit from the chapter titled The Decline of Slang, from the way we talk now, by Geoffrey Nunberg. (Grin, grin, and thank you, you know who you are!)

A lot of this language came from gypsies, tramps, and thieves and their cohorts, beginning in Shakespeare's time.
It became familiar to "polite society" in what were called Newgate novels in the 19thC., after the prison. He quotes from Vanity Fair: "Is that your snum? I'll gully the dag and bimbole the clicky in a snuffkin."

Mr. Nunberg says, "To Victorian ears, slang evoked a far more salacious tingle than it does for us...", and quotes an 1859 critic who says that slang may be as infectious as cholera, and that it should be equally discouraged from spreading.

"It wasn't until the Jazz Age that Americans began to lighten up on slang." The gangster movies and detective thrillers helped its acceptance enormously.

Following are quotes that I found very interesting, and would like to see others' opinions on, please. "But the romance of the underworld and its slang died shortly after the war, along with the notion of respectable society itself...But once the middle class cut loose, it no longer had to live vicariously through underworld language...But most modern slang is the language of hippies, surfers, hot-tubbers, yuppies, druggies, swingers, hackers, and the rest. They're people pretty much like anybody else. Slang doesn't hint at forbidden mysteries anymore."

Dear Jackie: I think the amount and complexity of slang is a function of the rapidly increasing complexity of our society. Imagine for instance what the "Yellow Pages" of Victorian England would have looked like compare to today's. It would probably have been less than a tenth of today's in size. And every Yellow Page has its own repertoire of slang.

...Slang doesn't hint at forbidden mysteries anymore

As society liberates itself from its own oppression , these have become *personal mysteries (i.e. each with the perceivers' individual interpretation).

This reminds me of an old saying that was applied *liberaly when we were kids - "That's for me to know and for you to find out".

Much of what Jackie calls "slang" would be better characterized as "argot". Victor Hugo devoted several chapters to Parisian argot in Les Miserables -- very interesting, but not worth reading unless you read it in French, since it translates awkwardly.

Does this mean that people opposed to all slang are argonauts?

Love it, Max! Personally, I am partial to argonaughty words.