First Language

母语、母语或母/父/母语言(也称为动脉语言或L1)，是一个人从出生时或在关键时期接触到的语言。在一些国家，母语指的是一个民族的语言，而不是自己的母语。说一种以上语言长大的孩子可以有一种以上的母语，并且会说两种或多种语言。相比之下，第二语言是指除了母语之外的任何一种语言。

A first language, native language or mother/father/parent tongue (also known as arterial language or L1), is a language that a person has been exposed to from birth[1] or within the critical period. In some countries, the term native language or mother tongue refers to the language of one's ethnic group rather than one's first language.[2] Children brought up speaking more than one language can have more than one native language, and be bilingual or multilingual. By contrast, a second language is any language that one speaks other than one's first language.