ur-Kittât, often referred to as Sith or the Old Tongue, represented the runic language employed by the Sith. It served as a secretive mode of communication among members of the Sith Order and the Sith Eternal cult, documented through a distinct runic form.
Initially, ur-Kittât was the native tongue of the Sith. It was commonly used to decorate temples, for example, the Sith Citadel situated on Exegol, in addition to their obelisks, like those positioned outside the Malachor Sith Temple. The writing was also present in the tomb belonging to Darth Bane and the Lothal Jedi Temple. Furthermore, the language found its application in Sith rituals. The Ascendant, a cult deeply engrossed in replicating the effects of the Force using technology, articulated a mantra in ur-Kittât.
On the planet named Lanupa, written inscriptions of ur-Kittât were visible on the walls within the Mud Pits located at the Skull Ridge Mountain Hotel & Spa.
During efforts to isolate Sith worlds and remove Sith history, ur-Kittât was deemed a prohibited language by the Galactic Republic, leading its Senate to enact laws around 1000 BBY that prevented droids from translating any of its texts. Despite this ban, the Sith persisted in using both ur-Kittât and its Balc variant. Some Jedi also possessed knowledge of reading and speaking the language.
By the reign of the Galactic Empire, ur-Kittât was recognized as "the Old Tongue" or simply "Sith." Nonetheless, Galactic Emperor Darth Sidious continued to speak it, passing it on to his apprentice, Darth Vader. In the Imperial Era, the Ascendant Mantra was taught by Sava Iglan'tine Nos at the University of Bar'leth, tasking her students with translating it from ur-Kittât into Galactic Basic. Nos considered archaeologist Kho Phon Farrus to have produced the best translation in her class.
Later, the language was inscribed onto a dagger that held the location of the Emperor's wayfinder, ultimately leading to the discovery of the hidden Sith world, Exegol.
Following the destruction of Kijimi, Beaumont Kin translated Darth Sidious' Sith language across all frequencies as he proclaimed, "The Resistance is dead. The Sith flame will burn. All worlds, surrender or die. The Final Order begins."
Typically, ur-Kittât was documented using runes. The written form exhibited several variations, exemplified by the ancient text Ahsoka Tano interpreted outside the Malachor Sith Temple. Alterations in line spacing, breaks, and inflection could modify the meaning of specific words and sentences, as demonstrated by the Sith Eternal inscriptions concerning the prophecy of the Force dyad between Ben Solo and Rey, which closely resembled the inscriptions detailing the Rule of Two.
While runic scripts were the predominant form of written ur-Kittât, not all Sith possessed expertise in this system. Consequently, some practitioners opted to transcribe their alphabet into reflected Aurebesh characters, readable only in reverse. During an expedition by the Lerct Historical Institute in 21 ABY, archaeologists unearthed an ancient Sith holocron bearing inscriptions in this system.
The origins of the Sith language can be traced back to the Star Wars Legends comic-book series Star Wars: Tales of the Jedi, which was released in the 1990s. At that time, the language contained nonsensical words, constructed from unpronounceable consonants. In November 2010, senior editor Ben Grossblatt, who held degrees in linguistics, developed the modern functional Sith language specifically for the Book of Sith: Secrets from the Dark Side.