Human language is ordained according to certain rules and principles which “codify” the place of words in a sentence (syntax), the appropriate word usage (semantics), verb tense, and so on. For instance, we acquire, from childhood, the rule that English places the subject at the beginning of a sentence, followed by a verb, and, if necessary, an object. We would not change this order without the meaning becoming confused or completely nonsensical. Thus, we instinctively know that the proper form is “The cat eats the mouse” and not “The cat the mouse eats;” nor would we arrange words in this order: “The mouse eats the cat,” unless we really wanted to state something illogical, because English, unlike Greek, Latin, or German, does not decline nouns, and so requires words to occupy a specific position in a sentence.
These rules, which we acquire through interaction with the society around us, are collectively known by the name of grammar. Now, grammar is not something devised from nothing for the purpose of creating a new, intellectual science. It performs a function, that of explaining the “codes” of a particular language. But as we have just seen, these codes, which determine the place of words in a sentence, or codify the use of a certain word over another, are inherant to all languages, and they determine our own choice of speech whether we are aware of them or not; they exist before the science of grammar. The role of grammatical science, then, is to make manifest these pre-existing codes, it rationalizes them by defining them. We do not need to learn grammar to learn basic language skills and be properly understood. Yet, once we are aware of the existence of these rules, and understand their particularities, grammar can greatly improve our own speech, and be used to refine it. We can decide for or against the use of a word in a particular sentence structure, etc. It is as if we beheld language from above in order to better grasp it and use it.