Aspects of cross-variety Dinka tonal phonology

This thesis examines tonal phonology across varieties of Dinka (West Nilotic, South Sudan), a typologically unusual language. The sound system—particularly the suprasegmentals—of Dinka is highly complex; the language has a three-level vowel length contrast, a voice quality (phonation) contrast, and tonal contrasts. All suprasegmentals are both lexical and morphological. This complexity, combined with the fact that the language is monosyllabic, means that the morphology of Dinka is expressed almost entirely via its suprasegmental system. However, while ternary vowel length and binary voice quality are relatively stable across varieties of the language, tone is not. When approaching an undocumented variety–which is most varieties—it is impossible to know in advance the number of tones, their phonological specifications, or any contextual tonal processes. The high functional load of tone in the language, along with the the varying number of tones and extensive tone sandhi, has led to the mistaken impression that the tone systems of different varieties of Dinka cannot be compared, and that systematic correspondences do not exist (cf. e.g., Andersen 2014). In contrast, this thesis shows the ways in which tones correspond systematically across numerous varieties of Dinka. This is analogous to work that has been conducted on Sinitic languages (Lee 1997)—but unlike Sinitic, Dinka is historically unwritten, and also unlike Sinitic, there is no centuries-long documentation of tonogenesis and tonology. Moreover, this type of correspon- dence has not been described in African languages. Therefore, this work serves as evidence that tone behaves similarly across time and across space, even in languages that are completely unrelated. The thesis proceeds along two axes of investigation: cross-variety and within-variety. I find that the tones of Dinka correspond across dialects; correspondences are predictable via a combination of tone and the vowel grade system, alternations of vowel length and vowel quality that permeate every area of the language’s morphology. While this was suggested with regards to the noun number system in the Luanyjang and Agar varieties of Dinka (Ladd & Blum 2021), this thesis takes that idea further, exploring this question with regards to five varieties of Dinka and numerous areas of the language’s inflectional morphology. The thesis also includes two additional studies, highlighting the striking effects of tone in specific varieties of Dinka. The first investigates the tone system of the previously undocumented Ngok variety of Dinka, describing the variety’s tones and contextual tonal processes. The second describes the relationship between the High and Rise tones in the Bor South variety of Dinka. This includes an examination of floating tone—tones unattached to the segmental sequence, evident only from their effect on the surrounding tonal environment—as well as an exploration of alternations between the High and Rise tones that is suggestive both of tonal evolution in previous stages of Dinka, and of possible future developments in the language.