Xibe people living in Xinjiang are Qing dynasty colonists in the region. They clearly speak the same language as the Manchu did, which bears a question: Are the Xibe and Manchu people the same ethnic group? If not, how different were they socially, genetically and maybe linguistically?
It depends on how you define "Manchu." The Sibe (Xibe) were NOT the same as the Jurchen tribe, the one that is generally regarded as "Manchu." What IS true is that the Sibe lived in the center of present day Manchuria, next to the Jurchens. By that very loose definition, they are "Manchu."
The Jurchens defeated the Sibe (and others) in 1593, and took over their territory. The Sibe were peacefully absorbed under "Manchurian" (Jurchen) rule, and redeployed to Xinjiang, in China's northwest, where they were needed as a buffer against Russia.
The Xibe language has eight vowel distinctions compared to six for the Manchu. But their written language is a modified form of the Manchu, and overall, it can be considered a dialect of Manchu http://en.wikipedia.org/wiki/Xibe_people
So one can say that the Xibe people are "similar to" (but not the same as) the Manchu people.