Innovation of head-marking in Humburi Senni (Songhay, Mali)

Humburi Senni (HS), the Songhay language spoken in the town of Hombori in Mali, has innovated not one but two suffixal pronominal-possessor paradigms for nouns (inalienable vs. alienable), a suffixal pronominal-complement paradigm for (original) postpositions, and a suffixal Imperative Singular for verbs. These are absent (with one very limited, but important, exception) in other Songhay languages, including HS’s nearest genetic neighbor. The effect is that HS has veered sharply toward head-marking, which is virtually absent in other Songhay languages. However, its specific typological profile is unusual, with head-marking well-developed for nouns and adpositions but absent from nonimperative verbs/clauses. We can reconstruct the sequence of events (crucially involving the encliticization of opportunistically appended independent pronouns) that result in the attested paradigms. As a result of these innovations, plus another innovation involving the morphology of unpossessed nouns, an original Definite Singular suffix *-òó now has four reflexes — none of which is now definite. Neither language contact nor demographic disruption played a role in the innovations; instead, the initial catalyst for the head-marking was probably the monophthongization of 1sg proclitic *ay to *i, merging segmentally with 3pl proclitic *i.