A latitudinal gradient in the density of human languages in North America.
Proceedings of the Royal Society B: Biological Sciences
117 - 121.
The number of different species found in a given area of the Earth increases from the poles towards the equator for a wide range of terrestrial and marine organisms. A similar but opposite latitudinal gradient is also generally found in the size of the geographic range over which a species is found: range sizes are larger in more northern latitudes becoming smaller in the south, a phenomenon known as Rapaport's rule. Here we show that the density of human language-cultural groups in North America, at the time of contact by colonizing Europeans, also followed a strong latitudinal gradient qualitatively similar to that found in North American mammals. Six times, or more, different languages were spoken in a given area in southern latitudes, compared to the density of language groups nearer to the poles. In addition, the amount of territory over which the speakers of a given language were found increases with latitude: linguistic-cultural groups conform to Rapaport's rule. Finally, based upon a categorization of North America into 23 distinct major habitat types, we find greater linguistic diversity in areas of greater habitat diversity, independently of latitude. 'Linguistic ecology', or the examination of ecological factors associated with diversity in the number of linguistic groups, may shed new light on some features of cultural and linguistic evolution.
|Title:||A latitudinal gradient in the density of human languages in North America|
|UCL classification:||UCL > School of Arts and Social Sciences > Faculty of Social and Historical Sciences > Anthropology|
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