Mind your Ps and Qs

[2] According to Michael Quinion, "investigations by the Oxford English Dictionary in 2007 when revising the entry turned up early examples of the use of Ps and Qs to mean learning the alphabet.

The first is in a poem by Charles Churchill, published in 1763: "On all occasions next the chair / He stands for service of the Mayor, / And to instruct him how to use / His As and Bs, and Ps and Qs."

Another proposal is from the English pubs and taverns of the 17th century: bartenders would keep watch over the pints and quarts consumed by the patrons, telling them to "mind their Ps and Qs".

[3] Other origin stories, some considered "fanciful",[3] could come from French instructions to mind one's pieds (feet) and queues (wigs) while dancing.

[7][dubious – discuss] Quinion cites an apparently related expression of pee and kew for "highest quality" used in 17th-century English: "The Oxford English Dictionary has a citation from Rowlands’ Knave of Harts of 1612: 'Bring in a quart of Maligo, right true: And looke, you Rogue, that it be Pee and Kew,'" possibly the initials of "Prime Quality" (folk etymology).