Meanwhile, generativism which was introduced by Noam Avram Chomsky argues that in the matter of language, the concepts proposed by structuralism are too simple. If we want to understand how language is mastered and used by human, we have to separate what is called cognitive system, that is a system underlying the ability of human to use and master language. In other words, human since they were born unconsciously have system of language in their brain (competence). That is why this paradigm argues that language is innate not learned.
Generative grammar is founded on the idea that linguistics should create a "grammar" that allows us to (in theory) generate every possible sentence in a language using a set of rules. It is simply an abstract theory that allows us to make a list (in theory) of all sentences, given the time to do so (which would be infinite-- there are infinitely many possible sentences). With tricks like recursion, it is in theory possible to design such a grammar, although so far no perfect grammar for any language has actually been written. And in theory, such a grammar also exists in our heads as "linguistic competence", while something else explains how we actually use it to speak, an action called "linguistic performance"-- and that can be imperfect, with speech errors, etc.