Relatedness as a Factor in Language Contact

Contact-induced change among related languages has been considered problematic for language reconstruction. In this article, I consider several aspects of the theory of language change and ways in which contact might interact with language relatedness. I show that models of language change which extrapolate dialect-contact models to languages and subgroups are problematic, and fail to take into account the unevenness of degrees of difference between languages across families. That is, diffusability clines that apply to speech communities and dialects do not appear to be in evidence for languages and subgroups. I further show that many claims about relatedness as a factor in language contact are confounded by other factors that are distinct from language relatedness, such as geographical proximity. Claims about effects of language contact appear to reduce to the type of interaction that speakers participate in, rather than structural facts about their languages. I argue that our current toolkit for reconstruction is adequate to identify contact features. Finally, I provide a typology of cases where contact might be expected to be problematic for subgrouping.