Your correspondent must be kidding when he says
that OK came to us from Obediah Kelly a freight agent
who used to sign his initials on bills of lading.

Why, there are a dozen explanations more intriguing
such as an invention of the early telegraphers

or variant of okeh a Choctaw word meaning " it is so "
(which may account for Mrs. Nicholas Murray Butler's
horror at finding it in English drawing rooms in 1935
and, worse still, in The Oxford Dictionary)

or a corruption of the harvest word hoacky ast load brought in from the fields

or the identification letters for the outer keel
which used to be laid first by the early shipbuilders.

At one time it was even used as an incantation
against fleas
which may explain why some people
thought it had its origin in a sign
THE PEOPLE IS OLL KORRECT
painted by Thomas Daniels a local handyman
on a farm wagon drawn by twenty-four horses
carrying thirty-six young women dressed in white
to a Whig rally in a grove in Champaign County, Ohio

Another possibility is that OK stood for Old Kinderhook
the birthplace of Martin Van Buren
known to his supporters as The Sage of Kinderhook
and to his enemies as The Kinderhook Fox

but after five hundred of his loyal rowdies
using OK as a rallying cry were thrown out
of a Whig meeting
the Daily Express suggested that the word
was Arabic
which read backwards meant Kicked Out

The possibility I like best however is that OK
stood for Aux Quais where the French sailors
used to date American girls during the Revolutionary War

At any rate, OK is the first word
learned by immigrants
and makes them instant democrats.