There is no single person credited with coining the phrase.
It's likely the phrase emerged organically over time, reflecting the common perception of ancient Greek as a complex and unfamiliar language to those who didn't speak it.
Here's why:
* Ancient Greek was a prestigious language: It was the language of philosophy, science, literature, and government in ancient Greece.
* Many people didn't speak Greek: For those who didn't learn the language, it would have been a barrier to understanding these important areas of knowledge.
* The phrase reflects a common sentiment: The idea that something is "all Greek to me" encapsulates the feeling of being completely lost or confused.
Therefore, the phrase's origins are lost to history, but it's a testament to the enduring legacy of ancient Greek language and culture.