First language
01
母語, 第一言語
the primary language that a person learns and uses fluently from early childhood
例
His first language is Spanish, but he speaks English fluently as well.
彼の母国語はスペイン語ですが、英語も流暢に話します。
She grew up speaking Arabic as her first language.
彼女はアラビア語を母国語として話して育った。
