If you think about it, English can be confusing, especially to those first learning the language -- as George Carlin pointed out, we park in driveways and drive on parkways. While we take common phrases and idioms for granted, there's usually a back story. In "America's Secret Slang," host Zach Selwyn explores how terms like "slush fund" and "fly off the handle" entered the lexicon. Revelations include how the circus gave America the word "jumbo," how actors led to the word "upstage," and a connection between George Washington and the word "groggy."