*dnghū-, Proto-Indo-European root meaning "tongue."
It is the hypothetical source of/evidence for its existence is provided by: Latin lingua "tongue, speech, language" (from Old Latin dingua); Old Irish tenge, Welsh tafod, Lithuanian liežuvis, Old Church Slavonic jezyku "tongue;" Old English tunge "tongue; speech."
The origin of the ethnic name is uncertain; it traditionally is said to be from the old Germanic word *frankon "javelin, lance" (compare Old English franca "lance, javelin"), their preferred weapon, but the reverse may be the case. Compare also Saxon, traditionally from root of Old English seax "knife." The adjectival sense of "free, at liberty" (see frank (adj.)) probably developed from the tribal name, not the other way round. It was noted by 1680s that, in the Levant, this was the name given to anyone of Western nationality (compare Feringhee and lingua franca).
Middle High Indian dialect used in sacred Buddhist writings (the lingua franca of northern India from c. 6c. B.C.E.-2c. B.C.E.), 1690s, from Sanskrit Pali, from pali bhasa "language of the canonical books," from pali "line; canon" + bhasa "language."
name for a group of related native people in the Columbia River region of Washington and Oregon, from Salishan /činuk/, name of a village site [Bright]. The name was extended to a type of salmon (1851) and a warm spring wind in that region (1860). Chinook jargon was a mishmash of native (Chinook and Nootka), French, and English words; it once was the lingua franca in the Pacific Northwest, and this sense is the earliest attested use of the word (1840).
by 1944, from Italian linguine, plural of linguina "little tongue," diminutive of lingua "tongue," from Latin lingua "tongue" (from PIE root *dnghu- "tongue").