early 13c., "beg, implore," from Old French crier, from Vulgar Latin *critare, from Latin quiritare "to wail, shriek" (source of Italian gridare, Old Spanish cridar, Spanish and Portuguese gritar), of uncertain origin; perhaps a variant of quirritare "to squeal like a pig," from *quis, echoic of squealing, despite ancient folk etymology that traces it to "call for the help of the Quirites," the Roman constabulary. The meaning was extended 13c. to weep, which it largely replaced by 16c. Related: Cried; crying.
Most languages, in common with English, use the general word for "cry out, shout, wail" to also mean "weep, shed tears to express pain or grief." Romance and Slavic, however, use words for this whose ultimate meaning is "beat (the breast)," cf. French pleurer, Spanish llorar, both from Latin plorare "cry aloud," but probably originally plodere "beat, clap the hands." Also Italian piangere (cognate with French plaindre "lament, pity") from Latin plangere, originally "beat," but especially of the breast, as a sign of grief. U.S. colloquial for crying out loud is 1924, probably another euphemism for for Christ's sake.