Deep Speech

Deep speech is not a written language, and only serve as ann oral form of communication. It is characterized by gluttural and hissing sounds that shouldn't be possible to be uttered. The conjugation of the words don't make sense, the structure is completely alien, and it invades the mind echoing inside of it.
There is a reason the Void drives the mortal mind mad, and a language from its plane holds the same distorted powers, if to a lesser degree. It is the strangeness of the void made accessible to those foolish enough to study it.