But “It’s Greek to me” goes right back to the Romans.
The wiki seems to say the aphorism originates with medieval scribes and Shakespeare's Julius Caesar.
The actual ancient Romans are unlikely to have had such qualms, since at the time Greek was much more widely understood than Latin, so much so that many important roman works like Caesar's Memoirs and Marcus Aurelius' Meditations were originally written in Greek, with the Latin versions being translations.
Or it would have been if LLMs were sufficiently dependable anyway.