Study offers evidence that long countries give better protection to languages than those that are wide.
This article explains some of the research that Jared Diamond's hypothesis in "Guns, Germs and Steel" generated. More specifically, this particular research hypothesizes that in a given country, its primary axis of orientation (North-South, East-West or balanced) helps to predict the survival of indigenous languages. While I have some skepticism about Diamond's core thesis, this is a good extension for teachers that use Guns, Germs and Steel in their classes.
Via Seth Dixon