The phrase “it’s all Greek to me” (meaning “I don’t understand it, it’s unintelligible”) is a common enough one in English to be the name of an awful lot of Greek restaurants, as well as this blog. Quite a few other languages also use Greek as the stereotypical hard-to-understand language – mostly European languages like Portuguese, Spanish, or Norwegian, but also Persian/Farsi. The phrase seems to start turning up in English in the 17th century – the most widely-quoted example is from Shakespeare’s Julius Caesar:
CASSIUS: Did Cicero say any thing?
CASCA: Ay, he spoke Greek.
CASSIUS: To what effect?
CASCA: Nay, an I tell you that, I’ll ne’er look you i’ the
face again: but those that understood him smiled at
one another and shook their heads; but, for mine own
part, it was Greek to me.
The joke here – that it literally was Greek to Casca (who in actual fact would, like every well-educated Roman, have spoken Greek) – presumably implies the phrase was already reasonably well-established in English at this point. It’s often claimed to come directly from the medieval Latin phrase Graecum est; not potest legi (“It is Greek; it cannot be read”), supposed to be used by medieval scribes copying out manuscripts; whether this is the phrase’s direct origin or not, it’s fairly easy to see how Greek – the most ‘difficult’ or ‘foreign’-seeming language an educated medieval/early modern European might be likely to come across – may have gotten this supposed ‘unintelligible’ status.
A Greek person, on the other hand, would express the same meaning with the phrase “It’s Chinese to me” – as would speakers of various other languages including French, Dutch, Russian, and various Eastern European languages; it’s an alternative option to Greek in Spanish and Portuguese, too. In fact Greek and Chinese seem to be the most popular choices of “unintelligible” languages. A few others choose Arabic or Hebrew; Dutch seems to be unique in having a phrase “That’s Latin for me”, while English, of course, also has “double Dutch”. Pleasingly, the constructed language Esperanto has a phrase “it’s all Volapük [a rival constructed language] to me”.
The Chinese expressions seem to win for inventiveness, though: apparently, a Mandarin speaker might compare something they didn’t understand to “heavenly script”, while a Cantonese speaker might say that it was “like chicken intestines”. For the ancient Greeks, on the other hand, any language that wasn’t Greek was stereotyped as unintelligible: a ‘barbarian’ – a non-Greek – is someone who just makes ‘bar-bar-bar’ noises when they speak. So “It’s all Greek to me” in ancient Greek would be barbarizeis – “You’re speaking like a barbarian”. That’s less of a catchy blog title, though.