 Some researchers such as Jerry Norman hold that Sibe is a dialect of Manchu, whereas Xibologists such as An Jun argue that Sibe should be considered the "successor" to Manchu.Ethnohistorically, the Sibe people are not considered Manchu people, because they were excluded from chieftain Nurhaci's 17th-century tribal confederation to which the name "Manchu" was later applied.Sibe is mutually intelligible with Manchu, although unlike Manchu, Sibe has reported to have eight vowel distinctions as opposed to the six found in Manchu, as well as differences in morphology, and a more complex system of vowel harmony.