Eldian language (Anime)

The unknown writing is one of the two known writings existent in the universe of the Attack on Titan, along with the Walls writing. It is a mysterious writing that so far only Ymir has been confirmed to be able to read.

Description
The unknown writing is very similar to the Walls writing, although it is known to be a different language since none of the Scout Regiment members (possibly including Reiner, a warrior from beyond the Walls) present at Utgard Castle were able to understand it; with the only exception of Ymir. The reason why she can read the writing is still unknown.