Italian is my first language.

意大利语是我的母语。

His first language is Welsh.

他的母语是威尔士语。

English was his first language and he always had a terrific ear.

英语是他的第一语言，而且他的听力一直很好。

"My first language is French," says LeMaire.

她说：“我的母语是法文。”

It is also the first language of sport and science.

它也是体育和科学使用的第一语言。