Morphophonological interactions in Shilluk: an investigation into the tone system and suffixation patterns in the Gar dialect

Abstract

West Nilotic languages are known to have rich suprasegmental systems, and Shilluk offers a case in point. Previous studies on the Lwak dialect postulate nine tonemes in the tone inventory of Shilluk, which are High, Mid, Low, High Fall, Low Fall, High Fall to Mid, Late Fall, High Rise, and Low Rise (Remijsen & Ayoker 2019; Remijsen et al. 2019). In contrast to the southern dialect of Lwak, the northern dialect of Gar is relatively understudied. This gap in the literature motivated an investigation into the tone system of Gar. Based on the data collected from a native Gar speaker, this study postulates that the Gar tonal inventory has the same nine tonemes as that of Lwak. However, there is dialectal variation in the distribution of tone specifications. These differences can be explained by the loss of suffix hypothesis (Remijsen & Ayoker 2019), which motivated the subsequent investigation into the patterns of suffixation in Gar. This study shows that Gar has lost the suffixes -ɪ/-ɔ in areas of the grammar where Lwak shows -ɪ/-ɔ suffixation. Based on this between-dialect comparison and following Andersen’s (1990) diachronic analysis of ternary vowel length contrast and suffix loss in West Nilotic languages, this study postulates that Lwak reflects an earlier, conservative stage of the diachronic development of Shilluk, whereas Gar reflects a later, advanced stage. The suffix investigation further shows that in Gar, suffix loss only involves the loss of the segmental material. The tonal material of the suffix is preserved and interacts compositionally with the tonal specification of the stem syllable. This compositional interaction analysis provides an explanation for the dialectal variation between Lwak and Gar with respect to the distribution of certain tone specifications. It also offers insight into why Shilluk has a more complex tone system than its neighbouring West Nilotic languages.