The aklo language is older than any mortal tongue. Predating known history, it transcends worlds and space. Once this goal is achieved, we'll bring the aklo language to Pathfinder with a treatise on its origin and devastating potential, written by non other than Sandy Petersen himself.
We'll also include a list of 70 aklo speaking creatures from the Pathfinder Bestiaries, adapted and revised by Sandy and his design team.
Lovecraft did not invent the aklo language, but he added to its mythology. Aklo, according to the Mythos, was originally invented by the Serpent Men as a tool to describe and control the arcane world. The aklo language is extremely powerful, and when a mere human learns it, he invariably goes insane as his brain is forced to re-wire itself to take in the alien concepts of aklo.
If the human has a powerful enough mind, over time the brain sort of heals, and he is able to accept and deal with his new view of the universe. He may still seem insane to other humans, but the insanity is now controlled and focused. In other words, if the person is able to "come out of the over side" of aklo, his madness is now more like that of Dr. Frankenstein or Abdul Alhazred, rather than simply banging his head against a wall. But he is also now far more dangerous.