Siwai language
Motuna or Siwai, also known as "Telei, Rugara", is a Papuan language of Bougainville Province, Papua New Guinea. It is spoken primarily in Siwai Rural LLG. The current number of speakers is difficult to estimate since the latest figure (6,000 + 600) is from the 1970 census. Phonology. Consonants. The structure of the language is CV(C), with the coda being an archiphoneme realized as a glottal stop, glottal fricative, or a nasal (homorganic to the next consonant or velar if word-final). Grammar. Siwai is an agglutinating language that undergoes a substantial amount of morphophonological fusion. Heads and  dependents are both marked. It shows case on NPs. It is ergative/absolutive. It shows extremely complex prefixation and suffixation in verbs, kinship terms, classifiers, and numerals. It tends to be verb-final, with A and O in either order. NPs can be omitted when understood from context. Gender. Siwai exhibits five genders: masculine, feminine, diminutive, local, and manner. These are marked in the singular forms only since dual and paucal forms are all marked like diminutive and plurals are marked like masculine. These genders coexist with fifty-one semantic types, marked by classifiers. These in turn are combined with  numerals, demonstratives, and possessive pronouns. Number. The language has four numbers: singular, dual, paucal, and plural. Nouns show all four while pronouns are either singular and non-singular. First-person non-singular shows a distinction in inclusive and exclusive. Verbs. Verbs mark person and number of core arguments. It has split S morphology and active/middle voice distinction. Verbs also mark one of fourteen TAM categories. Structure. The verb structure consists primarily of suffixes: There are some verbs that are exceptions to this structure, such as the Definite Future suffix which requires no gender marking, and some TAM morphemes in  medial verbs. Valency. Siwai has four types of valency structure: Some verbs are ambitransitive and take either active or middle voice. The voice system of the language is thus a "verbal diathesis" where the configuration of core arguments determine the active or middle voice. Classes. There are five main verb classes, which are determined by which cross-referencing morphemes they take: Syntax. Similar to many other Papuan languages, Siwai has medial verbs which are in the middle of a sentence and indicate TAM and switch-reference.