Kessonic

The language for the ancient tribes of Humans from before the migration into the west of [Allatar
The Kesson people were tribal and kept very little in the way of written records, having a mostly oral record keeping tradition.
Some examples of their pictographic writing can be found on the ruins of holy sites in the eastern lands and on some ruins deep in the deserts where some ancestors of the Kesson are believed to have settled before moving on again. This means that most of the written language is lost, despite all of this, some spoken Kessonic in some forms has still survived, for some reason, the swear words and curses in this language seem to resonate deeply in the mind, especially among humans, and so phrases spread easily. 
These days, only the most learned scholar would be able to read the language and perhaps no one can actually speak it. 
It was said in the distant past, that the Kesson had a connection to the ancient spirits of the land and nature, the divine beings known referred to as the Protogods. It has been said that these beings taught the Kesson their language and writing, meaning Kesson is tied to the language of the creation of the world. Before The Last War, this was a branch f study of much promise, the ancient language of creation of the Protogods might well hold the power of creation or healing of the natural world. Unfortunately, since the calamity, none now remain who are interested in this area of study.

Common Phrases

"That decision will lead you to trouble" (Lit. "The wind blows up your arse that way")

"Unshallan't" "Get fucked"