Every one of us was taught grammar in grade school. We learned the rules of writing, how to construct sentences properly, when to use commas, how to avoid run-on sentences, proper diction and word choice and tons of other rules regarding how the English language "properly" works. But there's one thing we weren't really taught. In fact, most of us unquestioningly accepted these rules, rules like you should use "fewer" for countable items and "less" for things you can't count. We know how to use these rules, and by virtue of being able to speak the language, we also know how to use the grammar. But these two concepts of grammar are not the same. This raises so many questions. Where did these rules come from? What is grammar, really, and how do we define it from a linguistic point of view? Is there some kind of supreme authority on the English language that imposes these rules on all its speakers?
In a Tarantino-esque fashion, we'll start from the end and work backwards to answer these questions.
As for an authority on the English language, well, that concept is really absurd. You'll see many laypersons claim that a dictionary defines proper use, that the dictionary (though they often fail to choose which particular dictionary) definition is the true and only way to use a certain word. You'll see these same pedantic people point to style guides for writing and instructional textbooks as the be all end all authority on how sentences should be structured. Think, though, how many different dictionaries are there? Oxford, Websters, Urban? Which one to choose? And with style guides, APA, MLA, Chicago, Turabian? Which of these are or should be the final authority?
Here's the thing, many people will insist on a stringent ruleset for the English language, and in doing so, they're viewing grammar from a Prescriptivist perspective. Prescriptivism literally prescribes rules to be used (oh no, I used passive voice there) when writing and speaking. Not to be totally discounted, There ARE some contexts when this is a necessary imposition. But the caveat is that all language use is context dependent. For example in formal writing such as technical writing, legal briefs and documents, and academic papers and essays. But there are also other times when it's entirely unnecessary, such as informal communications on message boards, in certain blogs, and in casual conversation like text messages.
Such focus on context is where the roots of descriptivism in grammar come into play. I'll let you in on a little secret, dictionaries are descriptive by nature, not prescriptive. At their very core, dictionaries relay information about what words mean based on how they are used. It's why they're always evolving, the definitions always changing. Take the word "nice" for example. Today, we tend to use the word to describe something pleasant, or to denote kind personality traits in a person; it didn't always mean what it does today, however. Springing to life in the 14th century and derived from the latin word nescius, which meant ignorant, "nice" used to mean foolish, silly, or stupid. Google the etymology of the word and you'll see for yourself. Here is a link to its etymology. Over time, it began to take on a different meaning. Over the centuries "nice" moved from:
- 14th century (early): stupid and foolish
- 14th century (late): fussy and pedantic
- 15th century (late): dainty and delicate
- 16th century: precise and careful
- 18th century: agreeable, delightful
- 19th century: kind, thoughtful
- 20th century: suave, in great favor with the ladies (Fowler research)
From all of those changes over time, it has finally come to mean what it does today: pleasant, agreeable, kind. And you can bet it will continue to change.
I suppose that's the great debate between prescriptive and descriptive grammarians. When the language changes, and naturally it will evolve and change over time, the rules have to be rewritten. "But," they argue, "how can a rule be rewritten? it's a rule, changing it breaks the very essence of it being a rule." The predicament is much like the Red Queen in Alice in Wonderland. The faster the prescriptive grammarians run to keep imposing new rules on the changing landscape, the faster the landscape moves and changes, thwarting the efforts.
All that said, and as I mentioned earlier, Prescriptivism isn't inherently a bad thing All the time. I'll reiterate again, it's all about context. When writing academic papers, you'll want to follow the style guides and keep your papers formal. They exist because of context and to create consistency in writing and form. Context and audience? Those the most important things to consider in any discourse. The audience receiving the communication from the language will have certain expectations, and it's up to the crafter of the language to fulfill these expectations. You may use the word literally as an intensifier when talking with your friends (e.g. I literally could eat a million hamburgers right now!) but you wouldn't use it in that sense when describing a chemical reaction in a scientific research paper (e.g. the atoms literally exploded into a million pieces) when in fact the atoms did no such thing.
Now to answer that final question: what is grammar? Grammar is simply the structure of a given language and how it is constructed to produce meaningful communication. It is the rules of usage, but not the prescribed ones. It is simply the natural structure language speakers acquire when they naturally inherit their primary language. The rest of it--the contextual usage rules, the orthography, the phonology, the syntax--they're all part of the language and pieces of it to be studies, but one of them alone does not a grammar make. Proper usage isn't dictated by some English authority, really, "proper" usage is all about what is acceptable for the context and medium the speaker is using at that moment.