On the relation between structural diversity and geographical distance among languages: Observations and computer simulations

Abstract

Modern linguistic typology is increasingly less concerned with what is possible in human languages (universals) and increasingly more with the question “what's where why?” (Bickel 2007). Moreover, as several recent papers in this journal show, typologists increasingly turn to quantitative approaches as a means to understanding typological distributions. In order to provide the quantitative study of typological distributions with a firm methodological foundation it is preferable to gain a grasp of simple facts before starting to ask the more complicated questions. In this article the only assumptions we make about languages are that (i) they may be partly described by a set of typological characteristics, each of which may either be found or not found in any given language; that (ii) languages may be genealogically related or not; and that (iii) languages are spoken in certain places. Given these minimal assumptions we can begin to ask how to express the differences and similarities among languages as functions of the geographical distances among them, whether different functions apply to genealogically related and unrelated languages, and whether it is possible to distinguish in some quantitative way between languages that are related and languages that are not, even when the languages in question are spoken at great distances from one another. Moreover, we may investigate the effects that factors such as ecology, migration, and rates of linguistic change or diffusion have on the degree of similarities among languages in cases where they are either related or unrelated. We will approach these questions from two perspectives. The first perspective is an empirical one, where observations primarily derive from analyses of the data of Haspelmath et al. (eds.) (2005). The second perspective is a computational one, where simulations are drawn upon to test the effects of different parameters on the development of structural linguistic diversity.