Why do we say?

Did you know when you say OK you're making a political statement? Well, at one time you would have been. Now a staple of English vocabulary, OK only caught on after it was a campaign reallying cry for the 1836 presidential candidate Martin Van Buren, whose nickname was Old Kinderderhook.
That's just one of many English words and phrases that have evolved over the years, making up an important part of the language and culture and one of the most colorful expressions used in everyday English without necessarily knowing what it means.