This is beautiful.

I'd really like hints on how to guide my players (well, the one that would be interested) through the process of learning this language.

For example, a Rosetta stone might be a good start... It could be a declaration of the dead god-king's glory designed to be legible to any who approach this temple to his greatness. They would have to recognise that the shape of the dungeon resembled the symbols they'd seen, but hints could be dropped if they don't get that right away... I think it might be cool to have the second script on the Rosetta stone magically change to be a phonetic reading of the viewer's mother tongue. My players probably wouldn't notice that unless it changes visibly for everyone to the nearest character's mother tongue...