Segment 1: An expert panel on slang today. "Extra." "Mood." "We live in a society." "Fell off." Or, per one recent high-profile Twitter feud, "dog-walk" (verb, transitive). These are phrases you either get or you don't. But some of them aren't even new. We define them while also discussing where they come from, why we call them slang (and not just language) and how they spread to eventually become part of standard English. Peter Sokolowski , editor-at-large, Merriam-Webster Natasha El-Scari ,