Examples of occupations with a patter include the auctioneer, salesperson, dance caller, magician, and comedian.
From this, it became a slang word for the secret and equally incomprehensible mutterings of a cant language used by beggars, thieves, fences, etc., and then the fluent plausible talk that a cheap-jack employs to pass off his goods.
In some circumstances, the talk becomes a different sense of "patter": to make a series of rapid strokes or pats, as of raindrops.
[6] It is thus also used of any rapid manner of talking, and of a patter-song, in which a very large number of words have to be sung at high speed to fit the music.
A western square dance caller may interpolate patter—in the form of metrical lines, often of nonsense—to fill in between commands to the dancers.