The Deadtalker Cipher

We need to understand what went wrong with the Deadtalkers. For so many years, the Deadtalkers were simply responsible for maintaining the burial grounds and holding funerals for fallen warriors. From a recent raid, we've recovered a tablet from the grounds that is clearly written using a cipher, but it isn't one we've encountered before. If you can gather a ciphered scroll from one of the Deadtalkers, we can begin to put together the cypher and understand what's happened.