Trees and the Comparative Method

Freeing the Comparative Method from the Tree Model

A Framework for Historical Glottometry

By Siva Kalyan and Alexandre François

Since the beginnings of historical linguistics, the family tree has been the most widely accepted model for representing historical relations between languages. While this sort of representation is easy to grasp, and allows for a simple, attractive account of the development of a language family, the assumptions made by the tree model are applicable in only a small number of cases: namely, when a speaker population undergoes successive splits, with subsequent loss of contact among subgroups. A tree structure is unsuited for dealing with dialect continua, as well as language families that develop out of dialect continua (for which Ross 1988 uses the term “linkage”); in these situations, the scopes of innovations (in other words, their isoglosses) are not nested, but rather they persistently intersect, so that any proposed tree representation is met with abundant counterexamples. In this paper, we define “Historical Glottometry”, a new method capable of identifying and representing genealogical subgroups even when they intersect. Finally, we apply this glottometric method to a specific linkage, consisting of 17 Oceanic languages spoken in northern Vanuatu.