There is a challenging issue for linguistic typology which involves the relationships which might exist between societal type and aspects of linguistic structure. Linguistic-typological studies have provided us with insights into the range of structures available in human languages, but we do not yet have explanations for why, of all the possible structures available, particular languages select particular structures and not others. A legitimate sociolinguistic viewpoint would be that some social explanations may be available. The sociolinguistic factors suggested as being relevant are language contact versus isolation, and community size and network structure. This paper deals with this thesis from the point of view of Austronesian phonology, with particular reference to Polynesian phoneme inventories.