Phylogenetics of kinship

[Update: materials are now available at pamanyungan.sites.yale.edu/kinship]

I am presenting work at the upcoming LSA meeting with a former undergraduate student and a postdoc (Amalia Skilton and Hannah Haynie). We have been working on kinship structures in Australian languages, using a combination of the comparative method and phylogenetic trait analysis.

The basic idea is that we can use our hypotheses of family tree relationships among Australian languages to reconstruct aspects of linguistic and cultural systems. In this case, we’re using the structure of sibling systems; that is, how many distinctions speakers of different languages make when referring to siblings. English just has two basic terms: ‘brother’ and ‘sister’; Bardi, however, has three terms: oombarn for older brother, bola or babili for ‘younger brother’, and marrir for ‘sister’ (Note that the Bardi system is asymmetrical, with two terms for brothers but only one for sisters.) Yan-nhangu also has a three-term system, but their system has a distinction for ‘older brother’ (waawa) vs older sister (yapa), but one term for ‘younger sibling’ (yapayapa). There are four fairly common systems in Australian languages (two, a four-way system and the Yan-nhangu-type three-term system, are the most common).

We reconstructed the sibling terms probabilitistically and then compared them to reconstructions of kinship lexical items, using the comparative method. We found that where the terms could be reconstructed, there was a great deal of congruity between the probabilistic state reconstruction and the comparative method reconstruction. However,

This sort of work isn’t well motivated for all systems. For example, it would not make a lot of sense to work on phoneme inventories in this way, because the inventories do not change independently of the lexical items in which they appear. That is, just because two languages both have a phoneme /p/, it doesn’t necessarily mean that those /p/s are “cognate” (because /p/ in one language could be cognate with /w/ in another, for example).