One of the three inscriptions was written in Greek.
Explanation:
The Rosetta Stone was the key to deciphering the Egyptian hieroglyphs because it was written in three languages. The part of the content written in Ancient Greek was easily readable since language is well-known by scholars.
The Stone also included two forms of Ancient Egyptian, demotic script and hieroglyphics. Thanks to the provided translation, the hieroglyphic form of writing was deciphered.
