The basic language unit for communication of ideas is sentence. Since phrases are part of a sentence, the proper use of them has direct influence on the expressiveness and effect of a sentence.

交流思想的基本语言单位是句子，而词组是句子的一部分，因此词组运用是否准确，直接影响到句子的表达与效果。

youdao

By the way, in what I'm saying, I oversimplify by supposing that the basic unit of language is a word.

因为我想说的是，我们现在是把语言的基本单位简单化了。

耶鲁公开课 - 文学理论导论课程节选

Sometimes the basic unit is the phrase, but some other times the basic unit is the phoneme or if one's studying language as a system of writing it might be the syllable.

有时候基本单位是一个词组，有时候则是一个音素,也就是在写作的研究中的,一个音节。

耶鲁公开课 - 文学理论导论课程节选