Tone and registrogenesis in Quiaviní Zapotec

Tone and phonation type are known to show complex interactions. I argue that breathy vowels in one Central Zapotec variety, San Lucas Quiaviní Zapotec (Otomanguean, Mexico), has resulted from an original tonal contrast between the low and rising tones (registrogenesis), based both on language-internal and comparative evidence with other closely-related Central Zapotec varieties. The case of Central Zapotec is unusual in that the direction of the sound change is from a tonal contrast to a phonation contrast, while in other known cases the direction is usually the opposite.