All quotes and opinion about O. K. taken from the Oxford English Dictionary, which I forgot to mention. There is no evidence of the 'word' before 1839 when "Oll Korrect" and O. K. appeared in van Buren's "Old Kinderhook" campaign. I should add that the Tammany Democrats in New York created the "O. K' Club," after Old Kinderhook (M. v. M) who got the name from his home town, Kinderhook, NY.
'All correct,' from which the campaign attempt to rope in the great unwashed was modified, of course, is much older. Van Buren was a disciple of General and President Jackson ("Old Hickory"), who inscribed "all correct" as his comment on the correctness of material in some of his documents, thus Jackson may (but no evidence) have been the inspiration for the campaign slogan. Jackson has even been blamed for the first use of 'oll korrect,' but a paper I have seen quoted has his Ms. 'all correct' properly written.
H. L. Mencken, in his "The American Language," has a long discussion of all the potential origins put forth since O. K. appeared in 1839. His conclusions are those reached by Read, and noted in the OED.

There was a fad for comical abbreviations, some based on mis-spellings, back in the same time period, and this may cetainly contributed. Reminds me of the mindless abbreviations in computer lingo that even appear in posts to the august Mudcat.

I again caution about using 'dictionaries of misinformation,' etc., in researching origins of words, customs or history. Most are pot-boilers published with the hope of making money, not with the purpose of disseminating scholarship.