Why Is Tone Change Still Poorly Understood, and How Might Documentation of Less-studied Tone Languages Help?

Abstract

The study of sound change has focused overwhelmingly on segmental change, while general and typological knowledge about tone change (excluding tonogenesis) lags far behind. This paper probes several interrelated reasons for this. First, much work on tone languages includes only superficial or even no treatment of tone, and even when analyzed, tone systems may lend themselves to differing analyses that would be compared in historical linguistic work. As a result, reconstructions of presumably tonal protolanguages often omit tone, limiting the study of tone change. Furthermore, tone is often reported to change faster or more sporadically than segments, leaving more changes to unravel and/or less-regular sound correspondences to handle. Even when tonal correspondences are robust, the phonetic distance between cognate tones may be so great that the phonetic properties of reconstructable elements may be especially indeterminate. After discussing these interrelated challenges, they are illustrated with a case study based on recent documentation of the Chatino languages of Mexico. While some families of tone languages have received significant diachronic study, many of the world’s tone languages remain minimally documented or poorly understood. Therefore, endangered tone languages may provide crucial information for better understanding tone change – and sound change in general.