Based Off of What?

By Anne Curzan. I recently received this e-mail from a colleague: “I’m losing my mind reading papers with the expression based off of, which has become very widely used (rather than based on). What do you know about where it came from and how its meaning emerged?”
The answer to her question, at the time I received the e-mail, was “very little.” I too had noticed the construction and had the sense it was on the rise. A search of Google Books with the Ngram Viewer confirmed my suspicion. More...