Historical glottometry

Historical Glottometry is a method used in historical linguistics. It is a quantitative, non-cladistic approach to language subgrouping. The aim of Historical Glottometry (HG) is to address the limitations of the tree model when applied to dialect continua and linkages. It acknowledges that the genealogical structure of a linkage typically consists of entangled subgroups, and provides ways to reconstruct that internal structure by measuring the relative strength of these subgroups. This approach was developed by Alexandre François (CNRS) and Siva Kalyan (ANU). While the method was initially applied to Oceanic languages, in recent years it has been applied to a much broader range of language families. Historical Glottometry grew out of the observation that a large number of language families in the world form linkages (a term coined by Malcolm Ross), i.e. they evolved out of former dialect continua in which historical innovations tend to overlap. Such linkages do not conform with the Tree model often used in historical linguistics, which presupposes that innovations should be nested. This common situation is better approached using the Wave model. Inspired by dialectometry, the aim of Historical Glottometry is to provide an alternative, non-cladistic approach to language genealogy, while remaining true to the principles of the Comparative method developed by Neogrammarians in the 19th century. The fundamental principles of Historical Glottometry include the following: each subgroup is defined by exclusively shared innovations (a principle first expressed by Leskien [1876]), i.e. linguistic synapomorphies; subgroups are allowed to intersect (as expected under the Wave model); the “strength” of each subgroup is measured on a continuous scale (rather than subgroups simply being absent or present). That strength is assessed using two ratings, named cohesiveness and subgroupiness. One of the outputs of Historical Glottometry takes the form of a “glottometric diagram”.