TONAL OPACITY, ALLOMORPHIC CONSTRAINTS, AND THE DISTRIBUTION OF POLAR QUESTION MARKERS IN ARÁRỌ̀MÍ-UGBÉṢÌ YORÙBÁ

Abstract

This study investigates the interaction between tone, negation, and polar question formation in Arárọ̀mí-Ugbéṣì Yorùbá, a Central Yorùbá dialect spoken in southwestern Nigeria. The paper focuses on the clause-internal polar question marker [rà], which exhibits a striking restriction against co-occurring with the negative marker [é], despite the grammaticality of negative polar questions formed with the clause-initial marker [ʃàki]. Drawing on original dialect data, the study demonstrates that the restriction is fundamentally phonological rather than purely syntactic or semantic. The analysis shows that [rà] cannot be immediately followed by an unrepaired high-tone syllable. While high-toned verbs and preverbal tense-aspect markers satisfy this requirement through tonal modification or allomorphic alternation, the negative marker [é] remains tonally opaque and lacks a low-tone allomorphic variant. As a result, the tonal conflict created by the sequence [rà + é] cannot be repaired, leading to ungrammaticality. An Optimality-Theoretic account is proposed in which the interaction of markedness, faithfulness, and allomorph-selection constraints derives the observed pattern. The study contributes to ongoing discussions of tonal opacity, allomorphy, and the phonology–morphology interface, providing new evidence that phonological constraints can shape the distribution of grammatical morphemes in Yorùbá.