If you're reading this page, it's a safe bet that you know
English grammar. That is, you know how to put words together in
a sensible order and add the right endings. Whether or not
you've ever opened a grammar book, you know how to produce
combinations of sounds and letters that others can understand.
After all, English was used for a thousand years before the
first grammar books ever appeared. But how much do you know
about grammar? And, really, why should anybody bother to learn
about grammar at all? Knowing about grammar, says David Crystal
in The Cambridge Encyclopedia of the English Language (Cambridge
University Press, 2003), means "being able to talk about what it
is we are able to do when we construct sentences--to describe
what the rules are, and what happens when they fail to apply."
In the Cambridge Encyclopedia (one of our Top 10 Reference Works
for Writers and Editors), Crystal spends several hundred pages
examining all aspects of the English language, including its
history and vocabulary, regio