A Word, Please: Delving deep into the rules of hyphenation

A New York Times article on Hong Kong reported that “the territory erupted in monthslong protests last year over a proposed extradition law.” My eye stopped at “monthslong.”

The New York Times has its own house editing rules, so I can’t be sure that the term is wrong in its world. Before the newspaper laid off a large number of its copy editors a few years ago, I might have assumed the folks there knew what they were doing when they left the hyphen out of “monthslong.” But now, I’m less inclined to give them the benefit of the doubt. They should have gone with “months-long.”

My guess is that an editor who was well-versed in the rules for hyphenating suffixes wasn’t quite so well-versed in a more esoteric issue: how to know when a word is also a suffix. Getting a term like months-long right requires a clear understanding of both, starting with hyphenation rules.

Most people don’t bother to dive too deep into hyphenation rules. They’re wise not to. Hyphen errors are usually inconsequential. If you write that you saw a man driving a pickup, no one will lose your meaning just because you didn’t write pick-up. So there’s no need for most people to spend hours or days researching a surprisingly complicated set of rules about what to hyphen when.

There’s a rule for hyphenating compound adjectives like family-friendly: Use a hyphen if it helps.

There’s a rule for hyphenating nouns like “mix-up” and verbs like “self-regulate”: Always check a dictionary.

There’s a rule for hyphenating prefixes like “co”: Skip the hyphen, “coauthor.”

There’s a rule for hyphenating suffixes like “able”: Skip the hyphen, “workable.”

Then come the exceptions — lots of them — which render “happily married couple,” “co-worker” and “gentleman-like” all correct, even though they contradict the rules I just listed.

If you’re looking for a simple way to hyphenate well, just follow this guideline: Hyphenate adjectives, prefixes and suffixes only when the hyphen might help the reader. For nouns and verbs, check a dictionary if it’s important or go with your gut if it’s not.

If, on the other hand, you aspire to perfect hyphenation, choose a style guide like the Associated Press Stylebook or the Chicago Manual of Style, read through the myriad rules and exceptions, then reach for that guide repeatedly throughout your lifetime because there’s no way you’ll memorize them all. Oh, and it helps to know that the official guides often contradict each other, so all your efforts to be “right” could still make you “wrong” from an equally informed point of view.

But all that effort won’t save you from writing “monthslong” in place of “months-long.” Yes, you’ll know that suffixes are usually attached with no hyphen: teachable, fearless, clerkship. But who said “long” is a suffix?

It’s tempting to think of “long” as being just like “able” and “less” and “ship,” which are both words and suffixes. But “long” is not a suffix. It’s just a word. So the rules for hyphenating suffixes don’t apply.

How can you know when a word is also a suffix? The answer is in the dictionary. Look up “ship” and you’ll see entries for it as a noun, a verb and a suffix. Look up “less” and you’ll see it’s an adjective, an adverb, a noun, a preposition and a suffix. Then look up “long” and you’ll see it’s not classified as a suffix.

Once you know that, you can analyze what “months” and “long” are doing in a sentence before a noun like “protests.” They’re working together as an adjective, modifying the noun. So the rules for hyphenating compound adjectives say that, in most cases, you should hyphenate two words that come before a noun to modify it, giving you “months-long protests.”

The writer is the author of “The Joy of Syntax: A Simple Guide to All the Grammar You Know You Should Know.” She can be reached at JuneTCN@aol.com.

Support our coverage by becoming a digital subscriber.