Explain how the stone was used to decipher the unknown language of the ancient Egyptians.

Explanation:

When it was discovered, nobody knew how to read ancient Egyptian hieroglyphs. Because the inscriptions say the same thing in three different scripts, and scholars could still read Ancient Greek, the Rosetta Stone became a valuable key to deciphering the hieroglyphs. Mainly the Rosetta Stone helped scholars at long last crack the code of hieroglyphics, the ancient Egyptian writing system. ... Ultimately, it was French linguist Jean-Francois Champollion who deciphered the Rosetta Stone and cracked the hieroglyphic code.

I think it's the rosetta stone

Explanation:

It might be a different language though

no because we were not ready for war