/ Thesaurus / F Synonyms of first language Find synonyms for: Noun1. mother tongue, maternal language, first language, natural language, tongueusage: one's native language; the language learned by children and passed from one generation to the nextWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: tenacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language