You've probably heard the saying, "It's all Greek to me," which people sometimes say when speaking about a word or phrase or something that makes no sense to them. It can kind of imply a double level of confusion for us English speakers, since not only are the words some o' them furrin' constructions, they're even in a different alphabet than we're used to!
According to this bit at The Washington Post, the phrase has a Latin origin, which maintains the double layer of "huh?" because Romans used the letters we've come to use and Greeks didn't.
The diagram answers a question that you might or might not have thought of -- if we say, "It's all Greek to me," then what do the Greeks say?
University of Pennsylvania linguistics professor Mark Liberman did some digging into different languages to see what language they referenced as being so completely unintelligible that all unintelligible statements might as well be said in it. Turns out a lot of languages inherited that Latin phrase about the mystery of Greek, including the Poles, Portuguese, Norwegians, Swedish, Spanish, Persians (modern-day Iran) and Dutch. Some of those groups also use other languages as their fallback incomprehensibilese. The Macedonians, who are kind of cousins to the Greeks, suggest that stuff they don't get is all Spanish to them, so the Spanish are kind of returning the favor by aiming their shrugging at the Greeks.
The Greeks lay their confusion off on the Chinese. So do a lot of others. The Chinese say that stuff that makes no sense comes from Heaven, which is kind of ratcheting up the game a couple of notches.
All of this, of course, is stereotyping. Greek letters are actually very easy to understand, or else drunken undergraduates would not be able to memorize the Greek alphabet whilst pledging fraternities or sororities. And any American knows senseless gibberish has only once source: Washington, D.C.
(H/T Leah Libresco)