Slang invades the dominant culture as it seeps out of various subcultures. Some words fall dead or lie dormant in the dominant culture for long periods. Others vividly express an idea already latent in the dominant culture and these are immediately picked up and used. Before the advent of mass media, such terms invaded the dominant culture slowly and were transmitted largely by word of mouth. Thus a term like snafu, its shocking power softened with the explanation "situation normal, all fouled up," worked its way gradually from the military in World War II by word of mouth (because the media largely shunned it) into respectable circles. Today, however, a sportscaster, news reporter, or comedian may introduce a lively new word already used by an in-group into millions of homes simultaneously, giving it almost instant currency. For example, the term uptight was first used largely by criminal narcotic addicts to indicate the onset of withdrawal distress when drugs are denied. Later, because of intense journalistic interest in the drug scene, it became widely used in the dominant culture to mean anxiety or tension unrelated to drug use. It kept its form but changed its meaning slightly.
Other terms may change their form or both form and meaning, like "one for the book" (anything unusual or unbelievable). Sportswriters in the U.S. borrowed this term around 1920 from the occupational language of then legal bookmakers, who lined up at racetracks in the morning ("the morning line" is still figuratively used on every sports page) to take bets on the afternoon races. Newly arrived bookmakers went to the end of the line, and any bettor requesting unusually long odds was motioned down the line with the phrase, "That's one for the end book." The general public dropped the "end" as meaningless, but old-time gamblers still retain it. Slang spreads through many other channels, such as popular songs, which, for the initiate, are often rich in double entendre.
When subcultures are structurally tight, little of their language leaks out. Thus the Mafia, in more than a half-century of powerful criminal activity in America, has contributed little slang. When subcultures weaken, contacts with the dominant culture multiply, diffusion occurs, and their language appears widely as slang. Criminal narcotic addicts, for example, had a tight subculture and a highly secret argot in the 1940s; now their terms are used freely by middle-class teenagers, even those with no real knowledge of drugs.