A sociolinguistically oriented study of polysynthesis literature reveals one rather striking observation. Varieties often cited as being incontrovertibly polysynthetic include languages from many different language families and different areas of the world. But many of these languages have a number of social characteristics in common: they are spoken in relatively small, traditional, non-industrialized communities, over relatively small territories. This chapter suggests that this is not a coincidence. There seems to be considerable agreement in the literature, for instance, that polysynthetic languages are ‘highly’, ‘extremely’, or ‘extraordinarily’ complex. And the literature on polysynthesis abounds in descriptors referring to their complexity as ‘exuberant’, ‘unusual’, ‘spectacular’, ‘baroque’, ‘rich’, ‘daunting’, and ‘startling’. This tallies nicely with the suggestion (Trudgill 2011) that linguistic complexity is particularly associated with relatively small, isolated, stable communities which have dense social-network structures; and is relatively unlikely to be found in large, high-contact (for example urban, colonial, standard) language varieties.