A first language (also native language, mother tongue, arterial language, or L1) is the language(s) a person has learned 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. Sometimes, there can be more than one mother tongue, (for example, when the child's parents speak different languages). Those children are usually called bilingual.
By contrast, a second language is any language that one speaks other than one's first language.
Read more about First Language: Terminology, Significance, On Multilinguality
Famous quotes containing the word language:
“He had not failed to observe how harmoniously gigantic language and a microscopic topic go together.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)