Tariana is an endangered Arawak language from north-west Amazon. It is spoken by c.70 people in two villages on the Vaupes River, north-west Amazonia, Brazil. The Tariana language belongs to the Arawak language family (see Arawak Languages). It is spoken by about 100 people in the multilingual linguistic area of the Vaupe´s River Basin (northwest Amazonia, Brazil). This area is known (Aikhenvald, 2002b; Sorensen, 1967) for its multilingual exogamy: one can only marry someone who speaks a different language and belongs to a different tribe. People usually say: ‘My brothers are those who share a language with me’ and ‘We don’t marry our sisters.’ The other languages in this area belong to the Tucanoan family, and they are still spoken by a fair number of people. The basic rule of language choice throughout the Vaupe´s area is that one should speak the interlocutor’s own language. Descent is strictly patrilineal, and consequently, one identifies with one’s father’s language group. There is a strong cultural inhibition against ‘language-mixing,’ viewed in terms of lexical loans. In its grammatical and semantic structure, Tariana combines a number of features inherited from proto-Arawak, with the areal influences from Tucanoan in the form of grammatical calques and diffused patterns.