According to Chomsky's linguistics, language competence is the speaker's internal understanding of a language, and language use is his specific action in using the language; Language ability and language use are not consistent, and language use is not a direct reflection of language ability.

First, Chomsky's view of language

In his study of language, Chomsky found that there are many phenomena that cannot be explained by structuralist grammar and behavioral psychology. For example, a child can master his mother tongue at the age of five or six; At this age, children's intelligence is still underdeveloped, and it is quite difficult to learn other knowledge (such as mathematics and physics), while learning languages is so easy. This phenomenon cannot be explained by "whiteboard theory" or "stimulus-response theory"

At this point, neither "stimulus-response" nor "imitation-memory" can be established. Not only that, but what some children know seems to be impossible to teach. For example, the difference between He Lost His Pen and He Lost, and the difference between He told her to leave the party and He promised her to leave the party. Because of the difference between the two predicate verbs, the actor who left also changed. Moreover, what children hear is not all standard, and quite a few words are nonstandard, ungrammatical and simplified (such as "eating sweets" and "eating fruits" as Chinese mothers say).

But the child finally learned the standard language. This is obviously not a simple imitation. After all, children's contact with words in five or six years is limited, but the sentences that children can say are infinite.

Second, Chomsky's transformational generative grammar theory

Transformational generative grammar theory is also called "transformational grammar theory" and "generative grammar theory". It refers to a new structuralist linguistic theory. Chomsky, an American linguist, was founded in 1950s and 1960s. Describe the theoretical system of natural language generative grammar with symbols and deductive methods. The main contents are:

Language is basically not learned, it is a gift. Children are born with an internal brain mechanism for processing language symbols. With the development of children, this internal mechanism is stimulated under certain conditions, and children can naturally acquire language. Language is a structure. Suppose people have a natural "language acquisition device" called LAD. Deep structure refers to the basic grammatical relations and semantics in a phrase or sentence, which determines the connotation and meaning of the sentence and belongs to the basic part of grammar and language ability. The basic way of language generation is transformation. Transformation rules mainly include substitution, ellipsis, addition and transposition.

Deep structure is transformed into surface structure, such as initiative and passivity, statement and question, juxtaposition, etc. The surface structure of perception can also be transformed into deep structure to understand the meaning of sentences. This theory has caused a revolution in the field of western linguistics, which not only has a wide impact on philosophy, computer language, logic, education, communication and so on. It also promoted the emergence of cognitive psychology and psycholinguistics.