On March 23, 1839, the Boston Morning Post printed a strange abbreviation: O.K. It stood for "oll korrect," a deliberately misspelled version of "all correct." The joke was part of a fad in the 1830s where newspaper writers made up funny abbreviations using wrong spellings. Most of these abbreviations were forgotten within weeks. But OK survived. Nobody is entirely sure why OK outlasted all the other abbreviations. One theory is that it got a boost during the 1840 presidential election. Martin Van Buren's nickname was "Old Kinderhook," and his supporters formed the "OK Club." The word also appeared in telegraph messages because it was quick and easy to tap out in Morse code. What makes OK truly remarkable is its global reach. It has been adopted into almost every language on Earth. Japanese speakers use it. Arabic speakers use it. People in countries that have never had contact with the Boston Morning Post say OK every day. Linguists, scientists who study language, consider OK one of the most successful words ever created. It can mean "yes," "fine," "acceptable," or "I understand." It is flexible enough to fit almost any situation.