Abstract
Verbs in Dinka (West Nilotic, Nilo-Saharan) are largely monosyllabic, but nonetheless the language displays a rich inventory of inflectional and derivational forms realized through alternations of the stem vowel with a morphomic distribution. The inflectional paradigm is driven by two complementary alternations which Andersen (1993, 2017) characterizes in phonological terms: fronting, which changes a stem vowel /a/ to /epsilon/, and lowering, which lowers or diphthongizes all other stem vowels. Both look like they might have been produced by the assimilatory effects of suffixes which have now been lost. While this is undoubtedly the case with lowering (Andersen, 1990), we argue that fronting was due to morphological analogy, pace van Urk and Chong (2022). Strikingly, the result was a vowel alternation pattern otherwise unattested in the verbal system, and whose resemblance to a phonologically conditioned change is purely coincidental. Our proposed reconstruction reveals two noteworthy and typologically unusual properties of this analogical change: (i) it operated on the overall system of morphophonological alternations, not on individual paradigms, and (ii) its output was determined by the phonological ambiguity of the analogical model, which we take to be a novel route towards the emergence of morphomes.