The Ecology of Language Evolution
You are partly correct if you think this is another cute way of designating what is also known as sociohistorical linguistics. This course situates the causes of language change in changes in patterns of social interaction within a population, including those brought about by language contact. However, it is deeply grounded in the economic history of populations, assuming that the economic systems determine particular population structures, which in turn determine patterns of social interaction, thus who can interact with whom and where, what language variety can be used, and who is more likely to accommodate the other.
The course covers a wide range of factors identified as ecological, some of which are external to language and others internal. The approach is largely inspired by population genetics, focusing on activities of individuals, and addressing, within the frame of competition and selection, a central question: how do the varying decisions of individual speakers eventually converge to discernible community-wide evolutionary trends? This is the same kind of question that should be addressed regarding the emergence of norms.
The course also situates contact at the level of individuals, as they are the ones that make population contact possible and negotiate at every encounter which language variety must be used, which particular norm must be followed, and which particular features must be given up or emulated, while in some cases they also carry (over) influence from other language varieties they already know. Yes, in my book I characterize communicating individuals as the “unwitting agents” of language evolution, in an attempt to situate that “invisible/hidden hand” that drives evolution. But there is also an important reason why the term evolution is used in this course: we go beyond structural changes to deal also with such topics as language spread, language speciation, and language birth and death (including language endangerment of course) – more generally, colonization and language.