Slang tends to originate in subcultures within a society. Occupational groups (for example, loggers, police, medical professionals, and computer specialists) are prominent originators of both jargon and slang; other groups creating slang include the armed forces, teenagers, racial minorities, ghetto residents, labor unions, citizens-band radiobroadcasters, sports groups, drug addicts, criminals, and even religious denominations (Episcopalians, for example, produced spike, a High Church Anglican). Slang expressions often embody attitudes and values of group members. They may thus contribute to a sense of group identity and may convey to the listener information about the speaker's background. Before an apt expression becomes slang, however, it must be widely adopted by members of the subculture. At this point slang and jargon overlap greatly. If the subculture has enough contact with the mainstream culture, its figures of speech become slang expressions known to the whole society. For example, cat (a sport), cool (aloof, stylish), Mr. Charley (a white man), The Man (the law), and Uncle Tom (a meek black) all originated in the predominantly black Harlem district of New York City and have traveled far since their inception. Slang is thus generally not tied to any geographic region within a country.
A slang expression may suddenly become widely used and as quickly dated (23-skiddoo). It may become accepted as standard speech, either in its original slang meaning (bus, from omnibus) or with an altered, possibly tamed meaning (jazz, which originally had sexual connotations). Some expressions have persisted for centuries as slang (booze for alcoholic beverage). In the 20th century, mass media and rapid travel have speeded up both the circulation and the demise of slang terms. Television and novels have turned criminal cant into slang (five grand for $5000). Changing social circumstances may stimulate the spread of slang. Drug-related expressions (such as pot and marijuana) were virtually a secret jargon in the 1940s; in the 1960s they were adopted by rebellious youth; and in the 1970s and '80s they were widely known.