Lexicographer (lexicographress? lexicographatrix?) Erin McKean has published an interesting article in The Boston Globe about what it really means to "be a word." Too often, people lump spelling, slang, and voice in with "grammar"; if they find a wordish collection of letters, a new slang term, or an odd voice that they don't like or understand, they denounce it as being ungrammatical, which is just plain wrong.
The world of words is much more wide open than grammar is. People rarely coin new punctuation (please don't send me your arguments for smileys as punctuation), or create a new part of speech (this sentence has a noun, a verb, and a predicate crickle), or cook up a new verb tense* (at least not successfully), but people create, rework, and repurpose new words all the time. That's one of the joys and beauties of the English language.
Words are the paint; grammar is just the canvas. (And semicolons are the colors that you can never seem to mix right.)
So my thanks and congratulations to Erin McKean for her article. I hope she was paid well.
* Sometimes we could use a new verb tense, though. When the time machine is finally invented, we'll need a new tense for an action that was performed in a person's past but that doesn't actually occur until the future. I'm gonna go home and watch Back to the Future now. Great flick.