"They" isn't singular:

Will Baude posted a defense of using they as a singular adjective, citing Shakespeare and Jane Austen as culprits in this regard. It's still wrong. "They" is plural, as evidenced by the fact that you use a plural verb with it. Period. "They" is not the third person singular; that is "he" or "she." It is a shame that English lacks a gender-neutral third person singular, but it does. Creating one wouldn't even necessarily be a bad thing, but it should be singular. That means it should take a singular verb, so "they" doesn't qualify. In eleventh grade, I was told to pick either "he" or "she" and use it exclusively in my papers instead of "they." Now, unless the person is almost certainly male (as in the case of the unknown author of Njal's Saga in the paper I just finished), I use "she."

"They" can't do double duty either. Number is a ternary construction. There are either zero people, one person, or some number of people, and this "or" is exclusive. I can't be both one person and many people since the two concepts are mutually exclusive. In English, really the verb determines the number. For regular verbs, there are only two choices; either there's an -s on the end or there isn't. If it's third person and there isn't an -s on the end, the subject is plural. After all, you told me it was plural because you picked a plural verb. And I've read that that means that we should say "you is" instead of "you are." Um, no. Try conjugating the verb "to be" sometime. Just because English conjugations are generally kind of simple doesn't mean that they don't exist.

And I know using "they" as a third person singular is more accepted in Britain, and anyone who reads this blog know I have some British spelling ticks (caused mainly by my complete inability to write a cursive z in elementary school and the fact that traveling just looks wrong to me, combined with weird backwards dating that are the result of German or some sort of weird leftover childhood Europe thing), but I don't turn in papers with "civilise" or "travelling" in them. I edit out my (incorrect) usage ticks when I'm writing academically because, you know, I go to school in America.

It's true that you hear and see "they" used as third person singular a lot. Doesn't make it right. People use it's as a possessive, too, but it isn't. Something that is fundamentally wrong isn't made right by lots and lots of uses.

If you aren't convinced that it's wrong, think of it like the first or second person singular. Perfectly fine in conversations and non-serious writing. Out of place in an academic paper.

And that may be why it's more OK in Austen or Shakespeare, since they aren't writing academic papers. Or maybe it can be explained away since they are British, and, you know, writing a long time ago. Just because Shakespeare used it doesn't mean it's OK in modern academic papers. You know, like contractions and weird constructions. Find me a reputable modern scholar who uses "they" as a singular in a published paper, since otherwise you're comparing apples to oranges.

"They" is not a third person singular. Once you add the plural verb, it's plural. It's fine in your everyday speech, but it isn't OK in an academic paper and Will's instructor was right to lay the smack-down.

(Though reading this post, the number of "they is" constructions that I've used makes a plausible case for they with a *singular* verb. It would sound terrible, though.)

(Also, I know that all the instances of "they" where I am talking about the word should be in italics, but that's too many keystrokes in HTML. Not happening).