Which detail from The Riddle of the Rosetta Stone by James Cross Giblin points to the big picture that hieroglyphs can represent sounds? A. They were accompanied by the figure of a bird, an ibis. Champollion knew from reading ancient Greek books that the ibis was the symbol of Thoth, the Egyptian god of learning and magic.
B. Champollion immediately thought of the one Greek leader whose name might be identified with this particular combination of letters. It was Alexander the Great, spelled "Alexandros" in Greek, and apparently represented as "Alksentrs" in hieroglyphs.
C. He succeeded in reading the names of all the Greek and Roman leaders who had ruled Egypt since the time of Alexander. He also translated the various titles adopted by these monarchs: "Caesar," "Great King," "Beloved of the Gods," etc.
D. This made Champollion think at once of the Coptic word for "give birth," which was pronounced mes. He put that sound in place of the question mark, and there the name was Ramesses, "The Child of Ra."