A Three-Hundred-Year-Old Dilemma

Recently The Economist’s “Johnson” column (named not for its author, but for the dictionary pioneer Samuel Johnson, who lived three centuries ago) ruminated on the frustrations and obscure consistencies of hyphenation. Apparently the magazine’s style book carries on about hyphens for eight pages, which to my mind leaves plenty to be said.

As they rightly point out, the path of hyphenation runs generally toward its disappearance: good-bye becomes goodbye, to-day becomes today, e-mail has widely transformed into email. Joining compounds as it does in so many ways, English distributes its hyphens not only by parts of speech but also by word origin, length, newness, and ease of reading. For instance:

Johnson also gets into the subtleties of syntax when considering the hyphen, e.g., “I have a zero-tolerance approach” (tolerance used as part of the adjective) versus “I have zero tolerance for that” (tolerance as a noun modified by zero). These differences really can matter, as in the example of “a third-world war” rather than “a third world war.”

But the most vexed hyphenation issue I run across did not pop up in Johnson’s article. I’m referring to spelled-out numbers followed by a reference to a measurement (age, time, distance, etc.). To wit:

Though most style guides call for all these hyphens, in practice many of us skip one or two, e.g. a twenty-five year-old car or a twenty-one month-old toddler. Insofar as hyphens exist to forestall confusion, it’s hard to see any confusion sown by either of these choices. I suspect, rather, that the convention exists more to create consistency between Arabic numerals and numbers spelled out, so that a 25-year-old woman is punctuated the same as a twenty-five-year-old woman. (And yes, we do spell out numbers greater than 10 at the beginnings of sentences, so these cases aren’t all that extreme.)

More interesting, and potentially more confusing, are instances where the noun is absent or implied. The following might seem weird in their hyphenation unless you assume a missing noun (suggested in parentheses) or take the latter part of the phrase to be itself a hyphenated noun. You can see here the differences in meaning:

In long number combinations, even when we restore the nouns being modified, we can see what a difference a hyphen or two can make:

In internet discussions, the most vexed hyphenation question in this category seems to arise when we add fractions. Thus we have no problem with the difference, say, between twenty-five years old and two hundred years old. But is it three and a half years old or three-and-a-half years old? The Corpus of Contemporary American English gives the nod to the former, but many people object to a long string of connected words absent hyphens.

It’s all very well to say, as Johnson does, that “this is one rule that need not drive anyone mad: a group of words used as a single modifier should be hyphenated.” But I suspect I am not alone in pausing, just about every time I need to spell out a number, to check my hyphen logic. What about you?

*Johnson gives this combination as hyphenated, but I imagine many of us distinguish between a slate-blue sky and a sky that appears slate blue.