Initiated by Haugen in the 1970’s, language ecology as a branch of learning is the study of the mutual effects language and environment play in the course of language communication, different from the structure oriented traditional linguistics. With its close relations to the sociolinguistic approaches to language contact, language decline and the like, the subject renders more attention to the effect environment plays upon language, which Haugen classifies into 10 aspects as its major concern. Mühlhɑusler advocates that linguistic ecology can achieve its purpose only with its involvement with a profound criticism of linguistic imperialism which undermines language ecology in Pacific region in specific and that of the whole world in general, and an adoption of holistic perspective of the effect taking all factors into consideration. Meanwhile, Tsuda pushes the subject matter further with his in-depth criticism of linguistic hegemony and introduction of the ideology of language equality and linguistic human rights.