Another legend is that in an Indian tribe in the U.S. state of Iowa, there was once a brave and upright chief known as Old Keokuk. He did not fear white people nor did he submit to tyranny. He kept his word throughout his life, and the treaties he signed with the government were validated by the two letters "OK." He disciplined his tribe internally and never broke his word externally, thus earning respect from all sides. Later, the U.S. government erected a statue for him and named an Indian reservation after him.
American railroad switchmen also initially used "OK." When they were on duty, if everything on the railroad was normal, they would say "All correct." Since the sound of "All" is close to "O" and "correct" is close to "K," for convenience, the workers shortened it to "OK" to express the same meaning.
In the late 19th century, "OK" began its expansion into the United Kingdom and around the world. Today, "OK" no longer evokes the stigma of illiteracy, and it is perfectly acceptable even when spoken by U.S. President Obama. In 2009, Obama told students: "That's OK. Some of the most successful people in the world are the ones who've had the most failures." British Prime Minister Cameron can also easily use the word in casual conversation.
However, although "OK" has dominated conversations around the world, it is still difficult to appear in many contexts. Most formal speeches and reports do not use the word. American novelists generally avoid using "OK," even writers like Mark Twain, who made extensive use of slang, were no exception.