“For the people and communities who claim endangered languages, however, the issues go far deeper. References to a ‘vanishing fund of human knowledge’, linguistic anthropologist Paul Kroskrity point out, elide ‘key connections to the larger role of threatened languages in the sociocultural lives of their speakers’, including the fight for sovereignty and the places of origin and identifications associated with the language (Kroskrity, 2011: 180).” (p xix)
Endonyms are the terms used by people within their own communities. Exonyms are the terms (in this case, English-language) used by outsiders to those communities. Using exonyms are much like calling someone “Susie” when they prefer to be called “Susan”  — using endonyms is a step toward showing respect for the identities of community members.
“Predictions for future growth suggest few signs of abatement, with estimates ranging from 6.4 to 8 million students studying outside their countries of citizenship by the year 2025 (Goddard, 2012; OECD, 2009).” (p 169)
“Studies of the family, the location of the significant choice of language, the maintenance of intergenerational language transmission or of the language shifting that marks changes of social and demographic environment typified by migration, urbanisation or conquest are therefore especially critical.” (p 6)
“Cognitive imperialism denies many groups of people their language and cultural integrity and maintains legitimacy of only one language, one culture, and one frame of reference.” (p 20)