Longman Dictionary of Contemporary English
Wiktionary
n. 1 the first language one is taught to speak; one's native language. 2 the language one feels most comfortable and capable with
WordNet
n. one's native language; the language learned by children and passed from one generation to the next [syn: mother tongue, maternal language]
Wikipedia
A first language (also native language, father tongue/mother tongue, arterial language, or L1) is the language or are the languages a person has been exposed to from birth or within the critical period, or that a person speaks the best and so is often the basis for sociolinguistic identity . In some countries, the terms native language or mother tongue refer to the language of one's ethnic group rather than one's first language. Children brought up speaking more than one language can have more than one native language, and be bilingual.
By contrast, a second language is any language that one speaks other than one's first language.
First Language is a peer-reviewed academic journal that publishes papers three times a year in the field of Language. The journal's editor is Kevin Durkin ( University of Strathclyde). It has been in publication since 1980 and is currently published by SAGE Publications.
Usage examples of "first language".
Manuel murmured in Tzotzil Mayan, our first language, the only one he had ever felt was his, far more than the English we spoke now, or the Spanish we had learned as a second language.
Both of them spoke in Italian, Cavriani's first language despite being born in Geneva, and one of the huge number Heinzerling spoke.
Please recall, sir, that both his mother and grandmother were English, and English was possibly his first language.
He stops before my trunk, then raises equipment designed to generate lights that mock the First Language.
No doubt they'd linked their translator programs with the printer, but humans whose first language wasn't Spanglish did that, too.