This past Sunday I had the opportunity to fill in once again for William Safire's "On Language" column in the New York Times Magazine. This time I focused on how the prefix un- is getting pressed into service for all sorts of new verbs — particularly in the novel lingo of social networking, where following, friending, and favoriting can be instantly reversed by unfollowing, unfriending, and unfavoriting.

Word Routes readers will know that these new un-verbs have been an interest of mine since writing back in May on the language of social media. The "On Language" guest column allowed me to probe further into the history of the un- prefix. In the column, I write:

Ever since Old English, the un- prefix has come in two basic flavors. It can be used like the word "not" to negate adjectives (unkind, uncertain, unfair) and the occasional noun (unreason, unrest, unemployment). Or it can attach to a verb to indicate the reversal of an action (unbend, unfasten, unmask).

Actually, that's a bit of an oversimplification. Yale linguist Laurence Horn, my trusty guide through the thickets of un-, points out that in Old English the two flavors corresponded to two distinct prefixes. On the one hand there was the negative prefix un- (etymologically related to German un-, Latin in-, and Greek a[n]-), and on the other hand there was the reversative prefix on(d)- (related to German ent- and Greek anti-). These two prefixes merged into one form, un-, and they've been semantically intertwined ever since.

So the new un-verbs that I discuss as typifying "The Age of Undoing" owe their legacy to the old reversative prefix on(d)-. But the other prefix in Old English, negative un-, could negate not just adjectives and nouns but some verbs too: unbe, unbecome, and unhappen are all attested in Old English with simple negative meanings ('not be,' 'not become,' 'not happen'). By the Middle English era of Chaucer, these negative verbs had faded away, so unlove (used by Chaucer in his poem Troilus and Criseyde) didn't have the meaning 'not to love' (negative) but rather 'come to no longer love' (reversative). And this is the type of unloving that has been handed down to modern-day country singers like Lynn Anderson ("How Can I Unlove You?").

There's one very peculiar register of Modern English when un-verbs have been used as simple negatives, akin to Old English unbe, unbecome, and unhappen. In the days when newspaper reporters filed their stories by cable telegram, they had to conserve the number of words used per message (something like Twitter's 140-character limit today). So the reporters would write their dispatches in a compressed code known as "cable-ese" or "telex language," which would then have to be decompressed by the editors back in the home office. As Douglas Starr recently told Wendalyn Nichols on her Copyediting blog, one trick used by Associated Press correspondents was attaching un- to verbs to mean 'not':

So, to save words — and money — and to prevent omitting not from stories, the AP combined words, and the rewrite desk in New York made the sentences read normally. It was like this. Instead of "does not have": "unhas." Instead of "does not know": "unknows." And "unwants," "unplans," "unwent," "unsaid," and so on.

It wasn't just the AP that used these negative un-verbs. Such cable-ese was well-known enough that the budding young newsman Charles Kuralt, while he was a student at University of North Carolina at Chapel Hill, used this insider jargon in playful letters to his friend Ken McClure. The website Remembering Charles Kuralt reproduces one of these letters (from May 1954), which begins:

EYE HOPE U UNMIND THIS NOTEPAPER IN LIEU OF RGLR LIVESPIKE STATIONERY MY FLOOZY PAPER UNARRIVED YET.

And later on, Kuralt writes:

EYE UNKNOW WHEN PLAN FNISH IT THINK OCTOBER.

These journalistic un-verbs even survive in the current digital age, long after reporters' cables have gone the way of the dodo. Ed Keer wrote on the American Dialect Society mailing list a few years ago that a friend of his at a "major news organization" says the shorthand is still used for internal communication: "'Unhave India-Tsunami, pls resend.' means 'I don't have the India-Tsunami story, please resend it.'" Occasionally this shorthand slips into public view: the photo service Getty Images sometimes accidentally leaves "unhave name" in a caption for someone whose name is unknown. That sort of error is, dare I say it, un-forgivable.