The word "okay" comes from central Africa. -- PCP
It's important to note, though, that the similarity of "okay" to the letters O and K in another language is not enough to establish an origin. You have to have a trail of historical evidence (at the moment, I think the best of those is for the Wolof term Wookay)... otherwise the meaning is lost. It's easy to come up with FolkEtymology -s for almost anything, especially as a BackroNym. Recall that "FolkEtymology" means "making up an origin based on what the word sounds or looks like, instead of actually researching". The newspaper editors who made up OK were practicing FolkEtymology as a joke that they had no idea anybody would take seriously.
To say okay derives from O.K., we must dismiss the evidence of millions of people speaking that word just before hundreds of citations of it appeared, as the two letters. But we must still trace words like "hippie" and "banana", which do not look like two letters, back to their correct language of origin.
The Oxford English Dictionary does not say the trail stops at Oll Korrect. It says they decline to pursue the trail further. But this means, if they use newspapers as their source, these are not interested in linguistics. The acronym OK appeared in newspapers in many different places, at around the same time, all as a joke that the people of the time would have got. Slaves say "okay" when you tell them to do something.
The correct etymological trail leads to diaries and journals written by slave owners. OED did not have this material in England and was not interested in pursuing it.
However, on a Web site dedicated to debunking that which appears in print, debunking bad ObjectOriented textbooks is okay here, but the OED is apparently off limits. This is sad.
The following from http://www.dictionary.com/search?q=okay -
Word History: OK is a quintessentially American term that has spread from English to many other languages. Its origin was the subject of scholarly debate for many years until Allen Walker Read showed that OK is based on a joke of sorts. OK is first recorded in 1839 but was probably in circulation before that date. During the 1830s there was a humoristic fashion in Boston newspapers to reduce a phrase to initials and supply an explanation in parentheses. Sometimes the abbreviations were misspelled to add to the humor. OK was used in March 1839 as an abbreviation for all correct, the joke being that neither the O nor the K was correct. Originally spelled with periods, this term outlived most similar abbreviations owing to its use in President Martin Van Buren's 1840 campaign for reelection. Because he was born in Kinderhook, New York, Van Buren was nicknamed Old Kinderhook, and the abbreviation proved eminently suitable for political slogans. That same year, an editorial referring to the receipt of a pin with the slogan O.K. had this comment: frightful letters... significant of the birth-place of Martin Van Buren, old Kinderhook, as also the rallying word of the Democracy of the late election, �all correct�.... Those who wear them should bear in mind that it will require their most strenuous exertions... to make all things O.K.
Source: The American Heritage® Dictionary of the English Language, Fourth Edition
Now I'm wondering where we got 'A OK'.
Grade A, 'okay' rating...
By the way "OK" is spelled "okay". It's a word, not an acronym. "OK" is just an old MorseCode thing.
That contradicts the explanation from the American Heritage Dictionary above... why do you say it's a word not an acronym?
See EtymologyOfOkay.
Briefly, all dictionaries cite the OxfordEnglishDictionary, written in England, based on USA newspapers. Before the 1830s there are dozens of citations for "OK" as a joke acronym, because the Wolof word "wookay" was entering the English language, just like Banana. Because the latter does not resemble an acronym, the peoples who were not allowed to publish newspapers in the 1830s get credit for it.