Diversity of languages
Linguistic diversity has many commonalities with species diversity, and the two disciplines are sharing methodologies. Few years ago, Gray and Atkinson (2003) showed a phylogenetic tree of Ind-European languages [1, see tree], a tree similar to those used in evolutionary biology. This is because languages contain a lot of historic information, like species. In this line, an interesting and recently compilation of papers show the state-of-the-art of evolutionary approaches to study cultural and linguistic diversity . For instance, we can see a phylogeneitc network of the Indo-European languages (see below, by Gray et al.) or the extinction trends of a language (e.g., the case of Gaelic in Scotland, by Kandle et al. [see figure]).
Jarret Diamond recently highlighted the benefits of learning several languages . Apart for the obvious social benefits, there are also health benefits of multilingualism like protection against Alzheimer’s dementia in old people . What it is unclear is whether the health benefits increase with the phylogenetic distance of the languages learned, or not. ... So there is still a lot of room for including evolutionary approaches in social and medical sciences.
 Gray RD and Atkinson QD 2003. Language-tree divergence times support the Anatolian theory of Indo-European origin. Nature 426: 435-439 (27 Nov. 2003).
 Steele J, Jordan P and Cochrane E (eds). 2010. Cultural and linguistic diversity: evolutionary approaches. Phil. Trans. R. Soc. B vol. 365 (no. 1559) [table of contents]
 Diamond J. 2010. The Benefits of Multilingualism. Science 330: 332-333 (15 Oct. 2010).
 Bialystok E, Craik FI, Freedman M. 2007. Bilingualism as a protection against the onset of symptoms of dementia. Neuropsychologia 45: 459-64
NeighborNet analyses of the Indo-European lexical data. Scale bar, 0.1. (Grey et al. 2010, Phil. Trans. R. Soc. B 365: 3923-3933).