"talk glibly or rapidly, chatter," mid-15c., from Middle English pateren "mumble prayers rapidly" (late 14c.), a shortened form of paternoster in allusion to the low, indistinct repetition of the prayer in churches. Perhaps influenced by patter (v.1). The related noun is first recorded 1758, originally "cant language of thieves and beggars," later "glib or fluent talk of a stage comedian, salesman, etc." Compare piter-pater "a babbled prayer" (mid-15c.), also Devil's paternoster (1520s) "a grumbling and mumbling to oneself." A pattercove in 16c. canting slang was a strolling priest.
PATTERING. The maundering or pert replies of servants; also talk or palaver in order to amuse one intended to be cheated. [Grose, "Classical Dictionary of the Vulgar Tongue," 2nd edition. 1788]
[T]he Pater-noster, up to the time of the Reformation, was recited by the priest in a low voice as far as 'and lead us not into temptation' when the choir joined in. [John S. Farmer, "Musa Pedestris," 1896]