Grammar is the structural foundation of our ability to express ourselves. The more we are aware of how it works, the more we can monitor the meaning and effectiveness of the way we and others use language. It can help foster precision, detect ambiguity, and exploit the richness of expression available in English. And it can help everyone--not only teachers of English, but teachers of anything, for all teaching is ultimately a matter of getting to grips with meaning.
(David Crystal, "In Word and Deed," TES Teacher, April 30, 2004)