Much like the neighboring people of the Kingdom of Khotan, people of Kashgar, the capital of Shule, spoke Saka, one of the Eastern Iranian languages. According to the "Book of Han", the Saka split and formed several states in the region. These Saka states may include two states to the northwest of Kashgar, and Tumshuq to its northeast, and Tushkurgan south in the Pamirs. Kashgar also conquered other states such as Yarkand and Kucha during the Han dynasty, but in its later history, Kashgar was controlled by various empires, including Tang China, before it became part of the Turkic Kara-Khanid Khanate in the 10th century. In the 11th century, according to Mahmud al-Kashgari, some non-Turkic languages like the Kanchaki and Sogdian were still used in some areas in the vicinity of Kashgar, and Kanchaki is thought to belong to the Saka language group. It is believed that the Tarim Basin was linguistically Turkified before the 11th century ended.