Abstract
In Nuer, a highly fusional and predominantly monosyllabic West Nilotic language, morphology is expressed primarily by stem-internal changes that affect vowel quality, voice quality, tone, vowel length and the stem-final consonant. This paper focuses on the interrelated alternations in vowel quality and voice quality, showing how these two parameters are used to encode inflection and derivation. Because the relation between the sets of the participating vowels is not systematic in a phonological sense, the alternations are analysed by postulating abstract morphological categories termed vowel grades. The proposed analysis enables us to unambiguously categorise the patterns of morphological marking on verbs, nouns, and adjectives. In addition, it simplifies the vowel inventory relative to earlier accounts. Finally, the proposed analysis contributes to our understanding of the diachronic development of vocalic phenomena in the West Nilotic languages. 1. Introduction Nuer (ISO 6393: nus / Glottocode: nuer1246), like closely related West Nilotic languages, stands out cross-linguistically in terms of the high functional load of fusional morphology across lexical categories. Lexical roots in these languages are predominantly monosyllabic, and morphology is expressed primarily through stem alternations-changes in the phonological parameters of the monosyllabic stem. In this way, stem alternations alone can express a wide range of derivational and inflectional information. Nuer differs from the rest of the West Nilotic languages in that it has an unusually large vowel inventory that amounts to 22 phonemes distinguished in terms of vowel quality and voice quality (Reid 2019, 2024). These vowel phonemes alternate in the morphology, as is shown in (1-2). The examples in (1) illustrate vowel alternations in nominal inflection. The alternations can involve changes in either vowel quality or voice quality. Changes in vowel quality are shown in (1a) where the alternation is between two monophthongs, and in (1b) where the alternation is between a monophthong and diphthong. The alternation in voice quality is shown in (1c) where the nominative has a breathy vowel (signalled by the diaeresis under the vowel) and the genitive has a modal vowel. The examples in (2) show alternations in verbal derivation. These alternations can involve changes in terms of both voice quality and vowel quality, as the modal vowels (2a,b) alternate with breathy vowels (2c,d) that also differ in terms of vowel height.