Dene-Yeniseian is a putative family consisting of two branches: Yeniseian in central Siberia and Na-Dene (Tlingit-Eyak-Athabaskan) in northwestern North America. Yeniseian contains a single living representative, Ket, as well as the extinct Yugh, Kott, Assan, Arin, and Pumpokol languages. Na-Dene contains Tlingit, spoken mainly in the Alaskan Panhandle, and a second branch divided equidistantly between the recently extinct Eyak language of coastal Alaska and the widespread Athabaskan subfamily, which originally contained more than 40 distinct languages, some now extinct. Athabaskan was once spoken throughout interior Alaska (Dena’ina, Koyukon) and most of northwestern Canada (Slave, Witsuwit’en, Tsuut’ina), with enclaves in California (Hupa), Oregon (Tolowa), Washington (Kwalhioqua-Clatskanie), and the American Southwest (Navajo, Apache). Both families are typologically unusual in having a strongly prefixing verb and nominal possessive prefixes, but postpositions rather than prepositions. The finite verb arose from the amalgamation of an auxiliary and a main verb, both with its own agreement prefixes and tense-mood-aspect suffixes, creating a rigid, mostly prefixing template. The word-final suffixes largely elided in Yeniseian but merged with the ancient verb root in Na-Dene to create a series of allophones called stem sets. Na-Dene innovated a unique complex of verb prefixes called “classifiers” on the basis of certain inherited agreement and tense-mood-aspect markers; all of these morphemes have cognates in Yeniseian, where they did not innovate into a single complex. Metathesis and reanalysis of old morphological material is quite prevalent in the most ancient core verb morphology of both families, while new prefixal or suffixal slots added onto the verb’s periphery represent innovations that distinguish the individual daughter branches within each family. Other shared Dene-Yeniseian morphology includes possessive constructions, directional words, and an intricate formula for deriving action nominals from finite verb stems.
Yeniseian languages have been strongly affected by the exclusively suffixing languages brought north to Siberia by reindeer breeders during the past two millennia. In modern Ket the originally prefixing verb has largely become suffixing, and possessive prefixes have evolved into clitics that prefer to attach to any available preceding word. Na-Dene languages were likewise influenced by traits prevalent across the Americas. Athabaskan, for example, developed a system of obviation in third-person agreement marking and elaborated an array of distinct verb forms reflecting the shape, animacy, number, or consistency of transitive object or intransitive subject. Features motivated by language contact differ between Tlingit, Eyak, and Athabaskan, suggesting they arose after the breakup of Na-Dene, as the various branches spread across northwestern North America.
The study of Dene-Yeniseian morphology contributes to historical-comparative linguistics, contact linguistics, and also to the diachronic study of complex morphology. In particular, comparing Yeniseian and Na-Dene verb structure reveals the prominence of metathesis and reanalysis in processes of language change. Dene-Yeniseian is noteworthy not only for its wide geographic spread and for the effects of language contact on each separate family, but also for the opportunity to trace the evolution of uncommon morphological structures.
Unbalanced bilingual acquisition as a mechanism of grammatical change
