A researcher believes that human language originally came directly from birds and primates, because if we re-examine modern human language, we can see how human communication evolved from the ancient communication mode system of birds and other primates; From other primates, we got the practical content of language
Human language consists of two different levels: the expressive level related to the variable structure of sentences and the lexical level expressing the core content of sentences
 Sometime in the past 100000 years, these abilities eventually evolved into the human language we know today