https://www.history.com/this-day-in-history/ok-enters-national-vernacular?cmpid=email-hist-tdih-2023-0 [login to see] 3&om_rid=
On March 23, 1839, the initials “O.K.” are first published in The Boston Morning Post. Meant as an abbreviation for “oll korrect,” a popular slang misspelling of “all correct” at the time, OK steadily made its way into the everyday speech of Americans.
During the late 1830s, it was a favorite practice among younger, educated circles to misspell words intentionally, then abbreviate them and use them as slang when talking to one another. Just as teenagers today have their own slang based on distortions of common words, such as “kewl” for “cool” or “DZ” for “these,” the “in crowd” of the 1830s had a whole host of slang terms they abbreviated. Popular abbreviations included “KY” for “No use” (“know yuse”), “KG” for “No go” (“Know go”), and “OW” for all right (“oll wright”).