Ordering towards disorder

In Athabascan languages, verbal morphological structure does not follow the cross-linguistically more common and stable ‘layered’ order: derivational and lexical affixes are not necessarily closer to the stem than inflectional affixes. While the emergence of the Athabascan order is understandable through different layers of grammaticalization (Mithun 2011), the question of why this order is relatively stable in the language family has not yet been satisfactorily answered. The distributional properties of cognate Athabascan morphemes reveal historical tendencies for fusion and reordering that suggest that affixes remain in or change their position depending on the semantic relevance to other affixes, not necessarily to the stem alone, as Bybee’s (1985) morphological theory would predict. An additional factor for the stability of non-layered structure of morphemes is the high degree of semantic generality found in affixes between the stem and other lexical and derivational affixes.