The Morphology of Yam Languages
This is an advance summary of a forthcoming article in the Oxford Research Encyclopedia of Linguistics. Please check back later for the full article.
The Yam Languages are a primary language family that is spoken in Southern New Guinea across an area spanning around 180 km west to east across both the Indonesian province of Papua and Papua New Guinea.
The Yam languages are morphologically remarkable for their complex verbal inflection characterized by a tendency to distributed inflectional exponence across multiple sites. Under this pattern of distributed exponence, segmental formatives, that is, affixes, are identifiable but assigning any coherent semantics to these elements is often difficult and instead the inflectional meanings can only be determined once multiple formatives have been combined. This raises interesting theoretical and typological questions about monotonic notions of morpheme and the isomorphic alignment of meaning and form. Yam languages are known for their complex inflectional morphology but display comparatively impoverished word formation or derivational morphology.
Nominal inflection is characterized by moderately large inventories of cases, the largest displaying 16 cases. Nouns may also be marked for number but this is typically restricted to certain case values. Verbal paradigms are also large; verbs mark agreement with up to two arguments in person, number, and at times natural gender. Additionally, languages display numerous tense, aspect, and mood values; this typically involves at least two aspect values, multiple past tense values, and some level of grammatical mood marking. Verbs may also be marked for diathesis, direction, and/or pluractionality.
Architecturally, nominal inflection is rather straightforward with nominal taking case suffixes or clitics with little to no inflectional classes. The true complexity lies in the organization of the verbal inflectional system and the prevalence of distributed exponence. While each language exploits distributed exponence in a unique manner, there are a number of architectural generalizations that can be made across the family. The languages display a remarkably similar inflectional template for verbs and inflectional classes are organized along similar lines. The primary inflectional class divide is between prefixing and ambifixing verbs. Prefixing verbs mark their agreement with a prefix only while ambifixing verbs mark agreement with the suffix, for monovalent clauses, or with both a prefix and a suffix for bivalent verbs. The verbal template involves these agreement prefixes and suffixes that also mark tense, aspect, and mood. The most prominent of those are a set of agreement prefixes known as undergoer prefixes, which mark tense, aspect, and mood in a non-transparent or morphomic manner.