also multi-lingual, "speaking, written in, or characterized by many languages," 1832, from multi- "many" + Latin lingua "language," literally "tongue" (from PIE root *dnghu- "tongue"). Related: Multilingually; multilingualism.
before vowels mult-, word-forming element meaning "many, many times, much," from combining form of Latin multus "much, many," from PIE *ml-to-, from root *mel- (2) "strong, great, numerous." It was much-used in forming Latin compounds in classical times and after (such as multianimis "having much courage," multibibus "much-drinking," multicomus "having much hair," multiloquus "talkative"). Many English words that use it (multinational, etc.) are 20c. coinages.
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."
<a href="https://www.etymonline.com/word/multilingual">Etymology of multilingual by etymonline</a>
Harper, D. (n.d.). Etymology of multilingual. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/multilingual