Aklo is a fictional language.
Aklo is a fictional secret language, possibly an artificial cipher or one used by a non-human race, associated with the writing of forbidden texts and evil cultists.
Aklo was invented by Arthur Machen in his 1899 story "The White People." It was later used in the works of H. P. Lovecraft who was a great admirer of Machen's work, appearing in his Cthulhu Mythos stories "The Dunwich Horror" and "The Haunter of the Dark."
In The Illuminatus! Trilogy by Robert Shea and Robert Anton Wilson, Aklo appears as a language used in Black Masses and by the Illuminati.
Alan Moore later used Aklo in his short story and 2003 comic The Courtyard. In his adaptation, Aklo is not just an alien language, but a key that opens doors inside the human mind. Like a supernatural alternative to phenomena such as Project MKULTRA, Alan Moore's version of Aklo contains certain trigger words or phrases which, when spoken in the right order while the listener has entered a different state of mind, usually reached through drugs, have a deep and permanent impact on the person. The first "dose" of Aklo forms a connection with the first level of a collective memory bank, whose origin from an inner or outer source contains memories and knowledge which are completely alien and inhuman in nature. This level makes the person ready and receptive to sink to a second level when receiving another dose of new trigger words, causing a new flow of hidden memories. After three doses, the main character in the story is no longer the same person as he used to be, and, although his behavior and new world view make perfect sense to him, he is actually behaving like a man that has lost all contact with reality.
The Pathfinder RPG, published by Paizo, uses Aklo as the language of several subterranean, otherworldly, or otherwise Lovecraftian species in the game's universe, such as aboleths and gibbering mouthers.[1]