The Creativity of Linguistic Khowledge
Knowledge of a language enables you to combine words to form phrases, and phrases to form sentences. You cannot buy a dictionary of any language with all the sentences of the language
because dictionary can list all the possible sentences. Knowing a language means being able to produce new sentences never spoken before and to understand sentences never heard before. The linguist Noam Chomsky refers to this ability as part of the creative aspect of language use. Not every speaker of a language can create great literature, but you, and all persons who know a language, can and do create new sentences when you speak, and understand new sentences created by others.