A friend of mine recently posted online a humorous observation to the effect that it’s ironic that non-hyphenation is hyphenated. In true word-nerd fashion, I figuratively cleared my throat and pushed my taped-together black horn-rimmed glasses up my nose before offering the deflating response that nonhyphenation does not in fact have a hyphen. (What are friends for?)
My friend’s misapprehension is a common one. Hyphenation in prefixed words remains rampant in writing ranging from social media posts to scholarly journals, though style manuals have more or less long advocated minimizing their use. Why, then, the persistence of non-profit, multi-billion (as in “multi-billion dollar budget,” which errs also in lacking a hyphen before dollar), pre-approved, post-modern, and the like?
First, some history: The hyphen began as an arc-shaped symbol called the enotikon, which was marked underneath letters in Greek script to denote a connection between two words. (The Greek term means “uniter.”) During the Middle Ages, a straight line with a similar role was adopted in Latin, and Gutenberg raised the symbol to the middle of the line of text, and furthermore adopted an angled double line resembling an equal sign at the end of a line, borrowing from writing of Latin script, when insufficient room remained to set an entire word with uniformly sized metal type, allowing him to break words to fit where necessary. (Many proofreaders who proof on paper still use an equal sign to denote a hyphen; the rationale for retaining the double line when marking proofs is that it is less likely than a single line to be missed or to be mistaken for an accidental mark.)
The trend in English is to phase out hyphenation when terms become more familiar. British English has also historically been more conservative than American English about retaining hyphens not only in prefixed words but also in compound nouns, as in dining-room or shop-keeper, which are now in both forms of English open and closed, respectively; many such constructions were purged from the Shorter Oxford English Dictionary only in the last decade.
Meanwhile, style guides strive to minimize inconsistency, but individual or regional preference and specialized occupational usage may resist progress. However, the most significant factor in the persistence of hyphens in prefixed words and in compounds may be that most people, including many professional writers, do not check dictionaries or style guides to verify or correct their assumptions, often relying on what they learned from (sometimes misinformed) teachers or from published resources—sometimes decades ago, before the hyphen became an endangered species in compounds and prefixed words.
To recap (not re-cap): Hyphens in such constructions are the exception, not the rule. (They do have valid applications, as many DailyWritingTips.com posts discuss; search the site for “hyphen” or “hyphenation” for examples.) If you are inclined to hyphenate a prefixed word or a compound word, double-check a dictionary or a style guide for prevailing style before you commit yourself. There’s no hyphen, and thus no irony, in nonhyphenated.