Drivers of geographical patterns of North American language diversity

Proceedings Royal Society B • Vol/Iss. 286(1899) • Royal society publishing • • Published In • Pages: 1-8 •
By Coelho, Marco Túlio Pacheco, Pereira, Elisa Barreto, Haynie, Hannah J., Rangel, Thiago F., Kavanagh, Patrick, Kirby, Kathryn R. , Greenhill, Simon J. , Bowern, Claire, Gray, Russell D. , Colwell, Robert K., Evans, Nicholas, Gavin, Michael C.

Abstract

Researchers investigated further into why and how humans speak so many languages across the globe, and why they are spread out unevenly. Using two different path analyses, a Stationary Path analysis and a GWPath, researchers tested the effect of eight different factors on language diversity. Out of the eight variables (river density, topographic complexity, ecoregion richness, temperature and precipitation constancy, climate change velocity, population density, and carrying capacity with group size limits), population density, carrying capacity with group size limit, and ecoregion richness had the strongest direct effects. Overall, the study revealed the role of multiple different mechanisms in shaping language richness patterns. The GWPath showed that not only does the most important predictor of language diversity vary over space, but predictors can also vary in the direction of their effects in different regions. They conclude that there is no universal predictor of language richness.

Note

While there are eight variables tested in both models, six of those are shown in the path model to indirectly effect language diversity by shaping population density, so only the hypotheses reported in the paper (using three independent variables) have been reproduced below.

Samples

Sample Used Coded Data Comment
Survey of California and Other Indian LanguagesPreviously coded
Native languages and languages of North AmericaPreviously codedGoddard (1996)
Global Self-Consistent Hierarchical High-resolution shoreline datasetUsed for high-resolution river maps
Terrestrials Ecoregions of the World datasetPreviously coded

Hypotheses (3)

HypothesisSupported
A larger number of individuals (greater population density) is positively correlated with a greater accumulation of languages (greater language diversity) (3).Supported
Higher potential carrying capacity with limits on group size is positively correlated with greater language diversity (4).Supported
Ecoregion richness is positively associated with language diversity, which implies that resource partitioning may contribute to language diversification (4).Supported
Documents and Hypotheses Filed By: abbe.mccarter  anj.droe