The northwest Amazon's sociocultural system of linguistic exogamy decisively depends upon the adjustment of patrilineal descent and patrilocal post-marital residence. This alignment contains that children speak the normatively anticipated language of their patrilineal descent group, at the same time the most broadly spoken language in the local community, mitigating its acquisition. Indigenous migration to Catholic mission centers in the 20th century and ongoing migration to urban regions along the Brazilian Rio Negro are reshaping the link between multilingualism and marriage. Multilingualism is quickly being hollowed out, with extensive language shift from minority Eastern Tukanoan languages to Tukano.