Kashima, Eri2020-02-262020-02-26b71497559http://hdl.handle.net/1885/201927This thesis is a mixed-methods investigation into the question of the sociolinguistics of linguistic diversity in Papua New Guinea. Social and cultural traits of New Guinean speech communities have been hypothesised as conducive to language differentiation and diversification (Laycock 1991, Thurston 1987, 1992, Foley 2000, Ross 2001), however there have been few empirical studies to support these hypotheses. In this thesis I investigate linguistic micro-variations within a contemporary New Guinean speech community, with the goal of identifying socio-cultural pressures that affect language variation and change. The community under investigation is the Nmbo speech community located in the Morehead area of Southern New Guinea. It is a highly multilingual community in the middle of the Nambu branch dialect chain, and consists primarily of the three villages Govav, Bevdvn, and Arovwe. The ideologically licensed speakers of Nmbo are the Kerake tribe people, but due to the practice of marriage exogamy, a large portion of non-Kerake people speak Nmbo as an additional language learnt from their parents or spouse. This thesis embraces the complexities of the multilingual ecology by including data from Kerake women who have married out of the Nmbo villages into the neighbouring Nen language village of Bimadbn. The empirical investigations bring data from three directions. First are the qualitative descriptions based on my own ethnographic fieldwork supported by prior ethnographic descriptions. The picture to emerge is of an egalitarian multilingual speech community. The qualitative descriptions also provide basic facts about demographics and social structures of the community. Second is the linguistic description of the Nmbo language. Nmbo is an under-described language without substantial prior description, and this thesis contains a sketch grammar covering the basics aspects of Nmbo grammar. Finally there are three quantitative studies of variation. The vowel sociophonetic study and the word initial [h]-drop study are classic Labovian variationist studies that investigate patterns of variation across a sample of speakers. The former is based of elicited word list data, and the latter on naturalistic speech data. The third quantitative study takes a grammaticalisation approach to an emergent topic marker in a topicalising construction from a relative clause construction. This is the first thesis ever produced providing qualitative, descriptive, and quantitative data from a New Guinean speech community within a language ecology of vital indigenous multilingualism. The contributions of the thesis are two fold. Firstly, this thesis brings grammatical and sociolinguistic descriptions from an under-studied language. It is a socio-grammar (Nagy 2009) that considers language ecology, sociolinguistics, and grammatical description. Secondly, this thesis contributes empirical data on the sociolinguistics of small-scale speech communities. The classic sociolinguistic variable of gender is not found to be particularly significant in the variables studied, despite the community being highly gendered in other social domains. Village, however, shows some significance. As far as the three variables are concerned, Nmbo speakers show little community-internal variation and paint a picture of a tight-knit society of intimates (Trudgill 2011). The conclusion to the question of the sociolinguistics of diversification is that while there is some evidence of sociolinguistic differentiation within the Nmbo speech community, the most important social groups to orient against are the other sister language groups in the Morehead area. The nascent variation within the Nmbo speech community, combined with the ethnographic evidence of a cluster of dense and multiplex social networks, suggest that should the social need to differentiate between other Kerake arise, linguistic differentiation may occur rapidly.en-AU202010.25911/5e58de79d5e15