Ashley posted this list on her blog today, and it made me think of how many little commonplace phrases and "witticisms" we throw into our daily vocabulary, unaware of their origins.
"It's all Greek to me" is one such commonplace saying; everyone knows what it means when they hear it. The first time I read "But, for mine own part, it was Greek to me," from Julius Caesar, I thought "A-ha! So that's where that came from!" But other authors around Shakespeare's time -- Thomas Dekker, for one -- also used similar phrases.
The phrase had been around much earlier than Shakespeare, though. There is a Medieval Latin proverb, "Graecum est; non potest legi", that translates literally as "It is Greek; it cannot be read," attributed to monk scribes. I would think, though, that Shakespeare's use of the metaphor in Julius Caesar is what brought it into modern day usage. I like knowing that it meant the same thing in the Middle Ages as it did in Shakespeare's time and as it does today -- "I don't understand you; you might as well be speaking Greek."
I wonder what Greek-speakers say when they want to accuse someone of being unintelligible?