I admit it: I expect my students to understand the rudiments of English grammar. Any day now, a black helicopter (chartered by legions of angry ex-students) will swoop down and take me away to some unimaginable hell-hole, where, for all eternity, I will be forced to read papers littered with comma splices.
Um. As I was saying.
It's very tempting, I think, for a student to regard grammar as "simply" mechanical. Hence the familiar cry: "But can't you just pay attention to what I've said, instead of how I've said it?" As I try to point out, you can't separate the "what" from the "how." Some grammatical errors lend themselves to making that point, like misplaced modifiers or incorrect prepositions. Still, there's something else at issue: reading. You can't analyze literature without first understanding grammar. If you cannot identify passive voice, tell the difference between a dependent and an independent clause, or find the subject, then many of literature's subtler points (and often some of its major points) will be--well--a closed book.
When does grammar come in handy? Before you embark on any serious discussion of Anne Finch's "A Nocturnal Reverie"(1713), you need to be able to do at least two things: a) recognize that the entire poem is a single sentence; b) find the main verb. As I've discovered from harsh experience, the grammatically-challenged reader will not be able to understand Finch's literal meaning, let alone anything else. Or perhaps you want to analyze Macaulay--the Victorian grand master of deadly parallels and paradoxes, semi-colons and subordinate clauses. It might be easy enough to summarize, say, Macaulay's brilliant assault on the poet Robert Montgomery. But without at least some awareness of grammar, it's difficult to explain how Macaulay so wondrously twists the knife in Montgomery's belly. ("There are words in Mr. Montgomery's writing, which, when disposed in certain orders and combinations, have made, and will again make, good poetry." Dale Peck, eat your heart out.)
In other words, I'm not interested in rote correctness; I'm interested in reading comprehension. Moreover, when I say "reading comprehension," I also mean the ability to comprehend one's own writing. I'll leave that for a different post.