1620s, from Italian, literally "Frankish tongue." A stripped-down Italian peppered with Spanish, French, Greek, Arabic, and Turkish words, it began as a form of communication in the Levant. The name probably is from the Arabic custom, dating back to the Crusades, of calling all Europeans Franks (see Frank). In 17c. English sources also known as Bastard Spanish.
c. 1400, intransitive (as of the tongue, from the mouth); transitive use by 1560s; see hang (v.) + out (adv.). Colloquial meaning "to be found" is recorded from 1811, "in allusion to the custom of hanging out a sign or 'shingle' to indicate one's shop and business" [Century Dictionary]. As a noun (often hangout) "residence, lodging" attested from 1893; earlier "a feast" (1852, American English).