There are several of the highlighted hieroglyphics that are also in some sort of code or something. For example, there's one in tunnel 3 in the room with the scarab puzzle (that you can't solve yet because it's missing a piece).
Luckily for us, this is a simple substitution code -- that is, one glyph stands for A, another stands for B, and so on. Read to the end of this hint for a translation of the message in the scarab room.
If you've never solved one of these kinds of puzzles before, start looking for patterns that repeat. THE is a very common word; in this puzzle, it's the first word in the last line.
Now that you know T, H, and E (T is a snake, H is a square spiral, and E is a cat), look for words like THAT and TO. Those two vowels will help you recognize other words, and you're on your way!
A one-letter word is either I or A.
In this case, it's I -- which means the two-letter word which follows it is probably AM.
Still having trouble? The first line is --
"Come ye hither gods in the train of Horus ..." And if that's not enough, here's the entire passage for you:
After you complete the first of these puzzles, you'll have the option to "Quick Translate" all the others, or you can solve each one yourself if you just enjoy the challenge. Also, all of the passages you've decoded will be written in the "Glyphs" book in your inventory, so if you need to remember them you don't have to also remember where they were.