The rise of mass communications and the concomitant spread of literacy to previously marginalized users of a national language present a problem to language historians who have heretofore had the luxury of dismissing variation attributable to imperfect learning and outright grammatical error. That is to say, what would have been ignored as a nondatum in the past must now be taken into account, especially if it becomes a constant presence in the written language. A prominent contemporary example in American English is the reinterpretation of the plurale tantum troops––strictly a collective or mass noun in traditional usage––as a count noun permitting the back-formation of a singular, troop.
Before the advent of the wars in Iraq and Afghanistan, the troops referred to a mass of soldiers, and the singular troop was blocked in this meaning. But with the prominent participation of the Marines along with the Army in these wars, the media followed the participants in discriminating between soldiers and marines, necessitating the use of a word that made no reference to whether the combatants belonged to a specific branch of the armed services. Herein lies the origin of the back-formed singular troop, with its status as a countable noun allowing locutions with numerals like “The insurgents killed 5 troops,” which remain ungrammatical for those speakers who adhere to the traditional norm.