Alexander Rafael

“One of Pagel’s graphs shows that the decreasing diversity of languages with latitude is almost identical to the decreasing diversity of species with latitude. At present neither trend is easily explained. The great diversity of species in tropical forests has something to do with the greater energy flowing through a tropical ecosystem with plenty of warmth and light and water. It may also have something to do with the abundance of parasites. Tropical creatures are subjected to a constant barrage of parasitic invasions, and being an abundant creature makes you more of a target, so there is an advantage to rarity. And it may reflect a lower extinction rate in a more climatically equable zone. As for languages, the need to migrate with the seasons must homogenise the linguistic diversity of extremely seasonal landscapes, in contrast to tropical ones, where populations can fragment into smaller groups and each can survive without moving. But whatever the explanation, the phenomenon illustrates the way human languages evolve automatically. They are clearly human products, but they are not consciously designed.”
― Matt Ridley, The Evolution of Everything: How New Ideas Emerge