linguo-, lingu-, lingua-, -linguist, -linguistic, -linguistical, -linguistically +
(Latin: literally tongue; and by extension, speech, language)
From Old Latin dingua which is a cognate (kindred) with Old English tunge, The change of d (in Old Latin dingua) to l (in Latin lingua) was probably due to dialectal influence (the so-called "Sabine l"). It was facilitated by a folk-etymological association with lingere, "to lick", the tongue having been conceived as "the licking organ".
Speakers of English may say, "What is his native tongue?" meaning language, and those who spoke Latin used lingua with the same figurative application. A linguist, then, is thought to be someone who speaks several languages fluently and is also known as a polyglot, literally, "many tongues".
Usually, when this person was bilingual; the next step probably was to be trilingual or even multilingual. From these stages of language development, we know that this person has learned diction, wording styles, idioms, phrasing, and vocabulary; as well as slang, jargon, and dialect because that is what linguistics is all about.
2. A letter or an articulation that is produced by a combination of the tongue and lips.