An Original Contribution to the Reconstruction of Proto-Yoruboid Phonology: New Evidence from Dialect Surveys

The reconstruction of Proto-Yoruboid, the ancestral language system from which Yoruba, Igala, Itsekiri, and related languages descend, represents one of the most consequential unresolved problems in West African historical linguistics. This dissertation advances the field by presenting new reconstructive evidence for Proto-Yoruboid phonology, drawn from systematic dialect surveys conducted in Kogi, Benue, Delta, and Ondo States, targeting previously underdocumented Yoruboid varieties. Using the comparative method in historical linguistics, data from 15 Yoruboid varieties including Owe, Yagba, Oworo, Itsekiri, and Idoani were collected through standardised Swadesh list elicitation, grammatical paradigm documentation, and minimal pair recordings from elderly native speakers. The study applies phonological correspondence analysis, internal reconstruction, and lexicostatistics to establish regular sound correspondences, posit proto-phonemes, and evaluate competing hypotheses about Proto-Yoruboid consonant and tone systems. Existing reconstructive work on Proto-Yoruboid by Capo, Williamson, and Blench has been constrained by limited data from North Central and Delta Yoruboid varieties. This dissertation makes an original contribution by incorporating new data from eight previously undocumented varieties. Findings are expected to revise the Proto-Yoruboid consonant inventory and provide new evidence for the evolution of the downstep system from a distinct proto-tonal contrast. Recommendations will address a collaborative Atlas of Yoruboid Dialects and the development of a digital Yoruboid comparative database. Keywords: Proto-Yoruboid, historical linguistics, phonological reconstruction, dialect surveys, comparative method.