This system, once invented, was developed during thousands of years.
Gradually the most important figures came to mean single letters or
short sounds like "fu" or "em" or "dee" or "zee," or as we write them, f
and m and d and z. And with the help of these, the Egyptians could write
anything they wanted upon every conceivable subject, and could preserve
the experience of one generation for the benefit of the next without the
slightest difficulty.
That, in a very general way, is what Champollion taught us after the
exhausting search which killed him when he was a young man.
That too, is the reason why today we know Egyptian history better than
that of any other ancient country.