Kara-Khanid Khanate
Modern Uyghur and Western Yugur belong to entirely different branches of the Turkic language family, respectively the Karluk languages spoken in the Kara-Khanid Khanate (such as the Xākānī language described in Mahmud al-Kashgari's "Dīwān al-Luġat al-Turk") and the Siberian Turkic languages, which include Old Uyghur.