Old English tunge "tongue, organ of speech; speech, a people's language," from Proto-Germanic *tungō (source also of Old Saxon and Old Norse tunga, Old Frisian tunge, Middle Dutch tonghe, Dutch tong, Old High German zunga, German Zunge, Gothic tuggo), from PIE root *dnghu- "tongue."
For substitution of -o- for -u-, see come. The spelling of the ending of the word apparently is a 14c. attempt to indicate proper pronunciation, but the result is "neither etymological nor phonetic, and is only in a very small degree historical" [OED]. In the "knowledge of a foreign language" sense in the Pentecostal miracle, from 1520s. Tongue-tied is first recorded 1520s. To hold (one's) tongue "refrain from speaking" was in Old English. Johnson has tonguepad "A great talker."
Bewar of tungis double and deceyuable,
Which with ther venym infect ech companye,
Ther poynaunt poisoun is so penetrable.
[John Lydgate, Fall of Princes (c. 1439)]
"to touch with the tongue, lick," 1680s, from tongue (n.). Earlier as a verb it meant "drive out by order or reproach" (late 14c.). Related: Tongued; tonguing.
"speaking (in a certain manner)," late 14c., in compounds and combinations, from tongue (n.).
"of or pertaining to the tongue," 1640s, from Medieval Latin lingualis "of the tongue," from Latin lingua "tongue," also "speech, language," from Old Latin dingua, from PIE *dnghu- "tongue" (source also of Old English tunge "tongue;" see tongue (n.)). Altered in Latin probably in part by association with lingere "to lick." Earlier "tongue-shaped" (c. 1400).
mid-14c., "serpent's tongue" (thought to be a stinging organ), later "sharp extension of a metal blade" (1680s), from a Scandinavian source akin to Old Norse tangi "spit of land; pointed end by which a blade is driven into a handle," from Proto-Germanic *tang-, from PIE *denk- "to bite" (see tongs). Influenced in some senses by tongue (n.). Figurative sense of "a sharp taste" is first recorded mid-15c.; that of "suggestion, trace" is from 1590s. The fish (1734) so called for their spines.
1856, from phrase to speak with one's tongue in one's cheek "to speak insincerely" (1748), suggestive of sly irony or humorous insincerity, perhaps a stage trick to convey irony to the audience.
Hem! Pray, Sir, said he to the Bard, after thrusting his Tongue into a Corner of his Cheek, and rolling his Eyes at Miss Willis, (Tricks which he had caught by endeavouring to take off a celebrated Comedian) were these fine Tragedies of yours ever acted? [anonymous, "Emily, or the History of a Natural Daughter," 1761]
This arietta, however, she no sooner began to perform, than he and the justice fell asleep ; but the moment she ceased playing, the knight waked snorting, and exclaimed,—'O cara! what d'ye think, gentlemen? Will you talk any more of your Pargolesi and your Corelli ?'—At the same time, he thrust his tongue in one cheek, and leered with one eye at the doctor and me, who sat on his left hand—He concluded the pantomime with a loud laugh, which he could command at all times extempore. [Smollett, "The Expedition of Humphrey Clinker," 1771]