Green’s Dictionary of Slang

(UK Und.) the tongue.

c.1566		Harman Caveat for Common Cursetours in Viles & Furnivall (1907) 82: a pratling chete, a tounge.
1592		Groundworke of Conny-catching [as cit. c.1566].
1608		Dekker Belman’s Second Nights Walk B1: A Prat-ling cheate is a tongue, Crashing cheates, are teeth; Hearing cheates are Eares.
1648		Dekker Canters Dict. Eng. Villainies (9th edn).
1665		Head Eng. Rogue I 51: Prating cheat, A Tongue.
1674		Head Canting Academy (2nd edn).
1688		R. Holme Academy of Armory Ch. iii item 68c: Canting Terms used by Beggars, Vagabonds, Cheaters, Cripples and Bedlams. [...] Pratling cheat, the Tongue.
c.1698		B.E. Dict. Canting Crew n.p.: Prating Cheat a Tongue.
1707		J. Shirley Triumph of Wit.
1725		New Canting Dict. [as cit. c.1698].
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. 1725].
1754		Scoundrel’s Dict. 19: The Tongue – Prating-cheat.
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1836		W.H. Smith ‘The Thieves’s Chaunt’ in Farmer Musa Pedestris (1896) 121: She’s wide-awake, and her prating cheat, / For humming a cove was never beat.
1862		E. de la Bédollière Londres et les Anglais 317/1: prating cheat, la langue.