Rakata (language)

Rakatan was the language spoken by the Rakata. When Revan was seeking the Star Forge the first time, he learned the language by ripping the knowledge away from The One, leader of a primitive Rakatan tribe. Upon returning during the quest to destroy the Star Forge, Revan found he still retained his knowledge of the language despite having had his memory wiped by the Jedi Council.

Historians believe that darth is a Rakatan word.

Source
Star Wars: Knights of the Old Republic