Geographic features responsible for biodiversity also shape human languages.
With 6,900 languages, humans have thousands of words for "mountain," ranging from ugwu in Nigeria to orqo in Peru and bundok in the Philippines. New research suggests that these landscape features, which also drive patterns of biodiversity, are key drivers of language diversity worldwide. Similarly, threats to biodiversity could also endanger human languages.
Researchers Jacob Axelsen and Susanna Manrubia compared language diversity in regions across the globe against 14 environmental variables such as temperature, precipitation, and altitude. Across all regions, landscape roughness (higher roughness indicates mountainous terrain) and density of rivers correlated best with language diversity.
In fact, landscape roughness and river density predicted up to 80 percent of the language diversity in Africa, and up to 69 percent of the diversity in Asia, Australia and the Pacific.
Both features, mountains and rivers, play different roles in language, the authors write. Mountains can isolate populations, giving rise to new languages. But rivers, as water sources, food sources and corridors of transportation, can bring diverse societies together and lead to hybrid languages.
In many ways, according to the authors, the factors affecting language diversity mimic those that affect biodiversity. For example, mountain ranges may isolate ecosystems, giving rise to new species, and rivers may bring different species together to create new hybrids.
The trends threatening biodiversity may threaten language diversity as well, the authors write in Proceedings of the Royal Society B, which published their results.
A changing climate may displace small native populations, disrupting linguistic traditions. And increased globalization, which can threaten biodiversity by introducing non-native species, has largely replaced river transportation -- once the route for people and languages to interact -- with long-range transportation.