学习语言必须遵循循序渐进的原则。

To learn a language we must follow the principle of gradual improvement.

《新英汉大辞典》

他在接受《新科学家》杂志采访时表示，语言必须以某种方式构建，否则就会更难使用。

Language has to be structured in a certain way, or it will be harder to use, he told New Scientist magazine.

youdao

随着时间的推移，语言必须负担更多责任。

Over time, languages have taken on more of that responsibility.

youdao

And so, any adequate theory of language has to allow for both the commonalities and the differences across languages.

因此,任何完善的语言理论,都必须谈及不同语言间的共性和差异

耶鲁公开课 - 心理学导论课程节选

The challenges that... First of all, you got to understand that learning a language takes time.

挑战就是，首先，你必须明白学习一门语言是件耗时间的事。

学第二外语的时候 - SpeakingMax英语口语达人

There's no language in the world that has a rule that says the fifth word has to be a verb.

世界上并没有语言规定,说第五个词必须是动词

耶鲁公开课 - 心理学导论课程节选