UchiTelle was a major regional dialect of TelleKurre, which was the primary language of the Domination. It was mentioned several times in The White Rose. UchiTelle was spoken and written by a specific ethnic subset of the broader TelleKurre population. This group also had their own style of weapons which could be spotted by antiquities experts like Bomanz centuries later.
After the Dominator's empire was overthrown during the first White Rose Rebellion, both UchiTelle and TelleKurre became extinct and were replaced with languages like Forsberger, Rosean, and others. Only the ghosts of White Rose soldiers who eternally haunted the Barrowland remained to speak it.
Less than 370 years later, even the educated wizard Bomanz could not read UchiTelle despite his mastery of TelleKurre. Only Raven, the Limper, and presumably the Lady were able to decipher UchiTelle by the time of The White Rose. Before the Battle of the Barrowland, the Limper corrected the errors made by Croaker and others who were attempting to transliterate UchiTelle names.