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

More speculatively, there has been some fairly recent work studying the genetic basis of language, looking at the genes that are directly responsible for the capacity to learn and use language.

更具体的来说,一些最新的语言遗传基础研究,探查了直接影响语言学习,及使用能力的基因

耶鲁公开课 - 心理学导论课程节选