First language (native language, mother tongue, or vernacular) is the language a person learns first. Correspondingly, the person is called a native speaker of the language. Usually a child learns the basics of their first language from their family.

The term “mother tongue” could be misleading. In some paternal societies, mothers are from different places and speak different dialects or languages, yet their children usually only speak their local language. Only a few will learn to speak his or her mother’s language like a native. Mother in this context probably originated from the definition of mother as source, or origin; as in mother-country or land.