Word Origin & History
O.E. tunge "organ of speech, speech, language," from P.Gmc. *tungon (cf. O.S., O.N. tunga, O.Fris. tunge, M.Du. tonghe, Du. tong, O.H.G. zunga, Ger. Zunge, Goth. tuggo), from PIE *dnghwa- (cf. L. lingua "tongue, speech, language," from Old L. dingua; O.Ir. tenge, Welsh tafod, Lith. liezuvis, O.C.S.
jezyku). The substitution of M.E. -o- for O.E. -u- before -m- or -n- was a scribal habit (cf. some
, etc.) to avoid misreading the letters in the old style hand, which jammed them together; and 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]. Meaning "foreign language" is from 1535. The verb meaning "to touch with the tongue, lick" is attested from 1687. Tongue-tied is first recorded 1529; tongue-in-cheek (adj.) is recorded from 1933, from phrase to speak with one's tongue in one's cheek "to speak insincerely" (1748), which somehow must have been suggestive of sly irony or humorous insincerity, but the exact notion is obscure.