Measuring Linguistic Diversity: A Multi-level Metric

This paper proposes a novel approach to the measurement of linguistic diversity. Drawing on the ecological literature, it proposes an adaptation to languages of the classic distinction between “alpha” (intra-setting), “beta” (inter-setting) and “gamma” (system-level) diversity. We begin by discussing some of the general challenges raised by the measurement of diversity. We review received approaches to the measurement of diversity resting on the concepts of richness and evenness, highlighting some limitations that come to the fore when comparing the respective diversity of different settings and systems. In order to overcome some of these limitations, we adapt the concept of “numbers equivalent” to linguistic diversity measurement indices. On this basis, we derive a multi-level approach to diversity measurement. We provide numerical examples to highlight the properties of this model before discussing its application to language policy issues.