H. Beam Piper 
Omnilingual [EPUB ebook] 

To translate writings, you need a key to the code—and if the last writer of Martian died forty thousand years before the first writer of Earth was born … how could the Martian be translated…?
An expedition from Earth to Mars discovers a deserted city, the remains of an advanced civilization that died out 50, 000 years before. The human scientists recover books and documents left behind, and are puzzled by their contents. Will they be able to translate them . . . is it even possible?