Hi, you may be interested in these threads:

On cuneiform

• When and how were cuneiform languages (like Akkadian and Sumerian) first deciphered by modern scholars?

• If Sumerian is a language isolate, how was it deciphered?

Egyptian hieroglyphs

• How sure are we that the Egyptian hieroglyphics and Mayan Symbols are actually what we think they are?

Various

• With computer technology at such an advanced point, why are there still so many undeciphered historical scripts?

• How do we know the prononciation of very old words from languages that are extinct by now?

Most of these posts have been archived by now, so if you have follow-up questions for any of the users, just ask them here & tag their username to notify them