Karun language

The language of Karun was held as sacred by ancient Ensaiten, as it was said The Creator himself entrusted the language to a group of wizards in the Ensaii area during the Era of Myths. It became known through a large portion of the world as a language of magic and used as such by many. As the Ages passed, Karun fell into disuse as wizards from different parts of the world learn to magic empower their own languages, making magic-dedicated languages such as Karun near enough obsolete.
The earliest records written in Karun still in existence are the Tablets of Lore, a series of stone tablets inscribed with the basic magical rules governing the various weaves of magical energies existing through the planes, how and where they connect, and how one with 'the Voice' - meaning someone imbued with a spark of magical talent - can make use of their voice and the magic within the words of Karun to manipulate the energies of the world.
Karun was initially only spoken within Ensaii lands. During the Age of Swords, Ensaiten expanded slightly and Karun followed with them. When Asashun invaded during the First Age of Darkness, the Asun mages were amazed by the power they could unlock with Karun at their disposal. As such, they did their best to learn and use the language as best they could. Karun was taken back to Asashun and used to develop new forms of runic magics, enabling the Dark Empire to expand throughout the Age of Knowledge and the Age of Peace to bypass the Black Desert and colonise the wetlands to the south.
Asashun ran prolific trade deals with various lands throughout the Age of Knowledge, which in turn spread the use of Karun through a good portion of the world. But as their magics solidified and the trend fi using local languages and dialect to work magic developed during the Age of Peace, Karun started to be used less and less. A lot of knowledge was destroyed during the Second Age of Darkness, including knowledge about Karun.