At present, the Sibe language is the only still-active oral variety of Manchu, the language of the indigenous tribe of Manchuria. With some 20,000 to 30,000 speakers it is also the most widely spoken of the Tungusic languages, which are found in both Manchuria and eastern Siberia. The Sibe people, who live at the northwestern border of the present-day Sinkiang Uyghur Autonomous province of China, are descendants of the garrison men of the Manchu army from the eighteenth century. After annexing the area, the Manchus sent the Sibe's predecessors there with the task of guarding the newly established border between the Manchu Empire and Russia. They remained isolated from the indigenous Turkic and Mongolian peoples, which resulted in the preservation of the language. In the 1990s, when the oral varieties of Manchu became either extinct or on the verge of extinction, Sibe survived as a language spoken by all generations of Sibe people in the Chapchal Sibe autonomous county, and by the middle and older generations in virtually all other Sibe settlements of Xinjiang. Spoken Sibe is a carefully researched study of this historically and linguistically important language.