First language

A number one language, native tongue, native language, mother tongue or L1 is the number one language or dialect that a grownup has been submission to from birth or within the critical period. In some countries, a term native language or mother tongue indicated to the language or dialect of one's ethnic group rather than one's first language.

The first language of a child is part of that child's personal, social in addition to cultural identity. Another affect of the first language is that it brings approximately the reflection & learning of successful social patterns of acting and speaking.[] Research suggests that while a non-native speaker may determine fluency in a targeted language after about two years of immersion, it can clear between five and seven years for that child to be on the same working level as their native speaking counterparts[].

On 17 November 1999, UNESCO designated 21 February as International Mother Language Day.

Bilingualism

A related concept is bilingualism. One definition is that a adult is bilingual if they are equally proficient in two languages. Someone who grows up speaking Spanish and then learns English for four years is bilingual only whether they speak the two languages with constitute fluency. Pearl and Lambert were the first to test only "balanced" bilinguals—that is, a child who is completely fluent in two languages and feels that neither is their "native" language because they grasp both so perfectly. This inspect found that