A tonal identification of Yoruba dialects

This article studies variations in the realisation of contour tones in Oyo, Ibadan, Ife, Igbomina, Ijebu, Ijesa, Ilorin, and Onko dialects of Yoruba and reports that the dialects exploit different dimensions of contour tone realisation to distinguish themselves. Ife, Igbomina and Ijesa dialects reduce the frequency of contour tones via high tone lowering and contour levelling, whereas Ijebu dialect multiplies contours in several ways. For instance, where the other dialects have MH and HH sequences, Ijebu has LH [LR], which increases its frequency of contour tones. In addition, Ijebu is the only dialect in which the M participates in contour tone formation whereby, ML sequence is realised MMUL. On the other extreme, Onko does not realise the falling contour at all. It is consequently argued that these dissimilarities between tonal contours are key indicators of dialectal variations among Yoruba dialects and they are more discernible than segmental and other grammatical indicators that have been more widely studied.