Enrico Canuto, Former Faculty, Politecnico di Torino, Torino Italy
While discussing the etymology of ciao, I observed that illuminating guides may be speaking and social contexts, as well as underlying expectations. In my opinion, the same way should apply to the enigmatic abbreviation OK (Italian pronunciation: o-‘(c)chei, with both vowels o and e open (or long), but e opener (longer) than o, thus producing a ‘jingle’ that neatly emerges from, closes or replies to a speech).
When I began saying OK to express agreement, satisfaction or approval? I was born just at the end of the II World War, when Italy was occupied by the Allies, and especially by the Americans who ostensibly deployed their 'shiny' way of life. In 1956 Renato Carosone (1920-2001) sang: ... Tu vuo' fá l' americano, mericano, 'mericano. Siente a me chi t''o ffa fá? Tu vuoi vivere alla moda, ma se bevi Whisky and Soda, po' te siente 'e disturbá. Tu abballe 'o Rock and Roll, tu giochi a Base Ball. Ma 'e solde p''e Ccamel, chi te li dá? La borsetta di mammá!? Tu vuó' fá l' americano, mericano, mericano, ma si' nato in Italy! ... Unavoidably, children, adolescents, young and also mature people in the fifties and sixties, tried to imitate Americans as conveyed by Carosone's song, but of course it was expensive. To say o-'(c)chei was a simpler, free of charge, yet attracting novelty and joke, that every people could practice.
OK is undoubtedly an abbreviation (better an acronym). The first written OK is recorded on page 2 of the Boston Morning Post on Saturday, March 23, 1839 . When, where and why acronyms have been used? Today, they are widely adopted by journalism, by science and technology and sometimes by bureaucracy. In the early XIX century, we should assume that only newspapers were, for obvious reasons – to save printing space-, the main publishing source. It is well known the political force of American newspapers in the campaign for American Independence and in the following years up to the present. By 1800, just 24 years after Independence Declaration in 1776, about 234 newspapers were published in the new republic.
Abbreviations and especially acronyms are per se word puzzles, which, hiding something unknown to be discovered, attract people attention and curiosity, but at the same time may annoy whether difficult to solve. The Boston Post was founded in November 1831 by two prominent Boston businessmen, and one of them, C.G. Greene, conducted it until 1875. For some reasons, he started or echoed in his journal an hilarious (and odd) way of inventing and reporting abbreviations, often deliberately arranged as misspellings for comic effects (maybe for attracting curiosity), like OK for ‘all correct’.
Page 2 of the Boston Morning Post on Saturday, March 23, 1839 (picture from https://www.quora.com/Whats-the-meaning-of-O-K)
It was the American scholar A. W. Read who masterfully explained the etymology of OK in a series of articles in the journal American Speech in 1963 and 1964 , . The answer of Cecil Adams in a question and answer column of the Chicago Reader , neatly summarizes the scholar’s findings:
Cecil replies: ... The letters, not to keep you guessing, stand for “oll korrect.” They’re the result of a fad for comical abbreviations that flourished in the late 1830s and 1840s. Read buttressed his arguments with hundreds of citations from newspapers and other documents of the period. ... The abbreviation fad began in Boston in the summer of 1838 and spread to New York and New Orleans in 1839. The Boston newspapers began referring satirically to the local swells as OFM, “our first men,” and used expressions like NG, “no go,” GT, “gone to Texas,” and SP, “small potatoes.” Many of the abbreviated expressions were exaggerated misspellings, a stock in trade of the humorists of the day. One predecessor of OK was OW, “oll wright,” and there was also KY, “know yuse,” KG, “know go,” and NS, “nuff said.” Most of these acronyms enjoyed only a brief popularity. But OK was an exception, no doubt because it came in so handy. It first found its way into print in Boston in March of 1839 and soon became widespread among the hipper element. It didn’t really enter the language at large, however, until 1840. That’s when Democratic supporters of Martin Van Buren adopted it as the name of their political club, giving OK a double meaning. (“Old Kinderhook” was a native of Kinderhook, New York). ... Van Buren’s opponents tried to turn the phrase against him, saying that it had originated with Van Buren’s allegedly illiterate predecessor, Andrew Jackson, a story that has survived to this day. They also devoted considerable energy to coming up with unflattering interpretations, e.g., “Out of Kash, Out of Kredit, and Out of Klothes.” ... As time went on, though, people forgot about the abbreviation fad and Old Kinderhook and began manufacturing their own etymologies. ...
The subsequent flourishing of the most bizarre etymologies  confirms the popular enigmatic feeling about OK, leading to an endless joke of interpretation and assonance, worldwide and free of charge dispensed by American civilization.
The unanswered question is: why the acronym and misspelling joke flourished in early XIX century among New England newspaper? The personal opinion, but I cannot prove it, is that the acronym and misspelling fad originated among newspaper typographers, both in their speech and writing. We should first recall that Boston and its area were, since XVIII century, a prominent typographic center of the new American republic. As a matter of fact, Boston area witnesses, all along the XIX century, technological improvement of printing presses as well as birth of book and newspaper companies . Second, the fact is that English spelling pronunciation of abbreviations, say AC (ei-si) for ‘all correct’, may be completely different from the actual pronunciation, that is ol kœ’rekt, where ‘k’ replaces ‘c’ as the latter is spelled ‘si’. This may imply that, in the hurry of a daily newspaper printing, AC (ei-si) could not be right away understood as the abbreviation of ‘all correct’ in favor of the enigmatic and odd OK (ou-key). It seems natural that a daily use of such misspellings could create at the same time apprehension and humor, and, in the end, the fancy of involving newspaper’s readers in the joke.
 Anonymous, OK, in The American Heritage Dictionary of the English Language, from https://www.ahdictionary.com/word/search.html?q=OK.
 Wikipedia, OK, from https://en.wikipedia.org/wiki/OK.
 C. Adams, What does “OK” stand for?, The Straight Dope, January 1985, from http://www.straightdope.com/columns/read/503/what-does-ok-stand-for
 J.M. Wells, American printing: the search for self-sufficiency, Proc. of the American Antiquarian Society, 1984.