"involving three languages," 1834, from tri- + Latin lingua "language," literally "tongue" (from PIE root *dnghu- "tongue"). Latin trilinguis meant "triple-tongued," and was used of Cerberus.
Entries linking to trilingual
tri-
word-forming element meaning "three, having three, once every three," from Latin tres (neuter tria) or Greek treis, trias "three" (see three).
*dnghu-
*dnghū-, Proto-Indo-European root meaning "tongue."
It forms all or part of: bilingual; language; languet; lingo; lingua franca; Linguaphone; linguiform; linguine; linguist; linguistics; multilingual; sublingual; tongue; trilingual.
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."