“That’s Greek to me” or “It’s all Greek to me” is an idiom used when you can not understand something. The origin might be in the old latin expression “Graecum est, non legitur”, which means “It is Greek, therefore it is illegible”. In the Middle Ages more a more monks were unable to read and therefor they were unable to copy from old Greek books.
We find similar expressions like “Greek to me” in other languages, but with a different language. The most extended is“It’s Chinese to me” o similar. In Central Europe, however, is“It’s Spanish village” thanks to the ingenuity of Johann Wolfgang von Goethe, who took the German idiom (see below) and change Bohemian for Spanish.
Our favorite ones are the grey ones, the unique and singular that we can not find anywhere else. For instance, Basques say “That is Latin to me”, which makes a lot of sense because, unlike all their neighbors, Basque language does not come from the old language from Rome. Similarly, for Italians Ostrogoth is a strange language. It should not be that much. Ostrogoths were germanic people who settled in Italy in the fifth century. However, all of the surviving written material is in Latin. Bulgarians say “It’s like your are talking in Patagonian“, which is a place not a language. Or is it? Nowadays Patagonia is the very south of South America. The term Patagão was coined by Antonio Pigafetta, who travelled with Magellan. Indigenous people speak a group of languages called Chonan.
“That is a Bohemian village to me” is a German expression that has an historical explanation. Centuries ago the Habsburg Monarchy reigned over the Kingdom of Bohemia. There Germans lived among Czechs without being able to understand each other.