If you browse the expat blogs, you’ll find gleeful posts tracking the dividing line between British and American English. And a wandering line it is. Are pants those things you wear under your jeans or are jeans one kind of pants? Is the fanny pack a bizarre medical procedure or a practical but geeky accessory? When you live your life in a semi-foreign language, all that stuff becomes important.

It also cues the kind of giggles you get when an eight-year-old has a chance to say “fart.”

Irrelevant Photo: Rocks near Minions, eroded by the wind. By Ida Swearingen

But pants and fanny aren’t even on the real dividing line. Only I know what really divides the Englishes: It’s the use of that and which.

I know: Speaking of geeky. Only someone who’s worked as a copy editor even notices, never mind cares.

I have worked as a copy editor, though, and I do. American publishing follows Strunk and White’s Elements of Style, and British publishing doesn’t. The distinction has to do with lawnmowers. You never thought of lawnmowers as a grammatical concept? See what you missed out on? Example A: The lawnmower, which is in the garage, is broken. This means we have one lawnmower. Example B: The lawnmower that is in the garage is broken. This means we have more than one, so use the other. I left it on the dining room table.

British publishing doesn’t care about lawnmowers. This—to a recovering American copy editor—is as shocking as wearing your pants inside your trousers.

It all has to do with restrictive and non-restrictive clauses and is too obscure to bother explaining. Which is lucky, since I don’t trust myself to get it right. And (she said defensively) you can be a perfectly competent copy editor and not be able to explain any of it. All you have to be able to do is apply it. It’s like not being able to explain electricity but knowing how to charge your phone.

Legend has it that Strunk and White introduced the that/which division because they thought it would be useful, if only it could be pounded into millions of recalcitrant little heads. In other words, they weren’t telling us about something that already existed, and so the aforesaid heads resisted the distinction because it wasn’t native to the language. But the owners of those heads still manage to mow their lawns and figure out, when and if it matters, how many lawnmowers they have.

So the that/which distinction is arbitrary and unnecessary, and in the long run the spoken language will always win out against the silly twits who tell us what’s wrong with the way we speak. But having made a career—such as it was—out of knowing this sort of stuff, it’s painful to watch as entire country consign it to the dustbin of irrelevant grammar. Even if it belongs there.

On an emotional and philosophical level, I’m on the side of spoken English, in all its barbaric glory. I’m not impressed with formal writing, for the most part. I believe that the language gains its power from use and that the hair-splitters are fighting a rear-guard action. If you break the rules of grammar idiomatically and well, the force is with you. And, in case you care, so am I.

On the other hand, I’ve read enough tin-eared writing to value the rules of grammar. Not because they keep us from barbarism and illiteracy, but because they keep us from incoherence. So I’m passionately on both sides of this battle, and if it ever turns violent both sides will call on me to shoot myself as a traitor.