Pastoral nomads speaking Ugric, Samoyedic, Turkic, Tungusic and Mongolic languages occupied most of North Asia when Russians arrived in the late 16th century. The forests of central Siberia were also home to Yeniseian-speaking hunters whose languages contained such areally unique features as a prefixing verb template, possessive prefixes, and phonemic tones. The surrounding families have vowel harmony and are exclusively suffixing. While the pastoralists acquired no grammatical traits from their hunter-gatherer neighbors, they significantly influenced Yeniseian morphosyntactic structures, as young brides from nearby reindeerbreeding groups entered the hunter-gatherer bands. Yeniseian developed a suffixing case system through grammaticalization of native postpositional constructions. Verbs shifted from prefixing to suffixing through reanalysis of inherited position classes with no borrowing of actual morphemes. This accommodation evolved farthest in Ket, the family’s sole surviving member today. The origin of other core Yeniseian features such as noun gender and plural suffixes on nouns remains unclear. External comparison with Na-Dene (Athabaskan-Eyak-Tlingit) - a North American family with which Yeniseian shares a genealogical link - can help clarify the original structure of the language ancestral to Yeniseian.