Advanced tongue root effect in Igbo affixation: perspectives from Èwùlù

AbstractÈwùlù (Igboid: West Benue–Congo, southern Nigeria) is a type 2IU dialect with a rather pervasive advanced tongue root (ATR) effect in its productive affixation morphology. Consequently, all vowels in affixes and those in adjoining root morphemes acquire the same value for ATR feature, with the latter morphemes determining with what specific ATR value the vowels in the former morphemes are specified. This sort of root-controlled ATR/vowel harmony system is yet to be independently explored in western dialects of Igbo (in particular, Èwùlù) spoken in Delta State, Nigeria. The goal of this article, therefore, is to describe the spread of ATR from roots to the adjoining affixes of the endangered dialect, with a view to advancing understanding of a typology of long-distance assimilation of vowel features across a string of vocalic elements in stems despite an intervening string of consonants. In order to insightfully capture the ATR-spread effect from roots to affixes, the study employs autosegmental theory, the mechanism of which uses association lines to link features to their specific melodic units operating independently on different tiers in phonological representations. The finding of this study showed this generalisation: if the dominant harmony feature of a root vowel is [+ATR], the adjoining prefix or suffix takes on the exact feature, otherwise it takes on the opposing feature, [−ATR].