Omnilingual by H. Beam Piper - Audiobook

Omnilingual by H. Beam Piper.
Read by Mark Nelson.

An expedition to Mars discovers the remains of an advanced civilization, which died out many thousands of years ago. They recovered books and documents left behind, and are puzzled by their contents. Would the team find their “Rosetta Stone” that would allow them to unlock the Martian language, and learn the secrets of this long-dead race?

(Summary by Mark Nelson)