and collars – it's all – one robe, So the Uzbek people are united, may they be in peace. Sufi Allayar (1633–1721) was an outstanding Uzbek theologian and one of the Sufi leaders of the Bukhara Khanate. He showed his level of knowledge by writing a book in the Turki language "Sabatul-azhizin". Sufi Allayar was often read and highly appreciated in Central Asia. The term Uzbek as applied to language has meant different things at different times. Uzbek was a vowel-harmonised Kipchak language spoken by descendants of those who arrived in Transoxiana in medieval period, who lived mainly around Bukhara and Samarkand. Turki was a Karluk language spoken by the older settled Turkic populations of the region (called Sarts) in the Fergana Valley and the Qashqadaryo Region, and in some parts of what is now the Samarqand Region; it contained a heavier admixture of Persian and Arabic, and did not have vowel harmony. It became the standard Uzbek language and the official dialect of Uzbekistan. According to the Kazakh scholar Serali Lapin, who lived at the end of the 19th – beginning of the 20th century, “there is no special Sart language different from Uzbek Russian researchers of the second half of the 19th century, like L. N. Sobolev, believed that: “Sart is not a special tribe, as many tried to prove. Sart is indifferently called both Uzbek and Tajik, who live in the city and are engaged in trade. In Khanate of Khiva, Sarts spoke a highly Oghuz Turkified form of Turki which belonged to the Karluk branch of the Turkic language family. Edward A. Allworth argued that this "badly distorted the literary history of the region" and was used to give authors such as the 15th-century author Ali-Shir Nava'i an Uzbek identity. All three dialects continue to exist within modern spoken Uzbek. Writing systems Uzbek has been written in a variety of scripts throughout history: 1000-1920s: The traditional Arabic script, first in the Qarakhanid standard and next in the Chagatai standard. This is seen as the golden age of the Uzbek language and literary history. 1920–1928: the Arabic-based Yaña imlâ alphabet. 1928–1940: the Latin-based Yañalif was imposed officially. 1940–1992: the Cyrillic script was used officially. Since 1992: Switch back to Latin script, with heavy holdover usage of Cyrillic. 2019: reform of the Latin script (planned) 2021: reform of the Latin script (planned) Despite the official status of the