Where did hieroglyphs come from?

How did the system of Egyptian hieroglyphs develop? do we have any surviving fragments of ‘proto-hieroglyphs’? did the system of hieroglyphs evolve over the centuries, so that an inscription can be dated from the style of hieroglyphs, or was the system fairly static?

Wikipedia: Egyptian_hieroglyphs#History_and_evolution

They came from Thoth. Didn’t they teach you any religion in school?

http://en.wikipedia.org/wiki/Thoth

How much has the language changed over the years. Obvoiusly no non-scholars read or write in hieroglyphcis anymore, but could a speaker of coptic Egyptian travel to 3300 BC and have any hope of understanding the spoken language?

A hieroglyph is a Rebus. You know the game, where you say the pictures aloud to make a phrase? A picture of an eyeball, a wood saw, and an ewe can be read as “I saw you.” Hieroglyphs work the same way.

It’s a bit more complex, because it also includes ideograms to distinguish between various words that sound alike.

Yes, it changed over time. When first invented, there were a few hundred standard symbols in use. Over centuries, this grew to several thousands. Each of them represented a specific syllable.

And then much later, they had a revolutionary idea. They invented a simplified system, using just 24 glyphs, from which it was possible to build any word.