How Low Can You Go? A Note on Vowel Mutation in Nuer

In Nuer, a Western Nilotic language, a productive process of vowel mutation lowers certain vowels in the plural forms of reduplicated adjectives, while others remain unaltered. Sometimes, lowering is accompanied by diphthongization. This short paper asks what determines which vowels should lower, which should also undergo diphthongization and which should remain unaltered. The phenomenon is analyzed within Element Theory in which vocalic expressions are decomposed into a head element and a dependent element. A pre-specified, Semitic-type template is proposed alongside a constraint on Head Preservation. These two tools derive the entire set of attested and unattested mutations. It is then shown that the analysis can pave the way for a better understanding of other, similar vowel mutation processes in Nuer.