The fundamental aim in the linguistic analysis

"The fundamental aim in the linguistic analysis of a language L is to separate the grammatical sequences which are the sentences of L from the ungrammatical sequences which are note sentences of L. The grammar of L will thus be a device that generates all of the grammatical sequences of L and none of the ungrammatical ones."

Noam Chomsky, Syntactic Structures, 2nd ed., Mouton (2002)