The three-part monograph contains new materials on the history of the Sogdian language - the international language of the Silk Road. The first part discusses the origin of a number of Sogdian words with unidentified etymology, the second part is devoted to the evolution of Aramaic elements in the Sogdian language, the third part contains the publication of two unique documents - a letter to the Sogdian prince Devashtich from the Arab emir and a marriage contract between the Turk and the Sogdian princess