An Optimality Theoretic Analysis of the Mid Tone in Isekírì

The asymmetric behaviour of the mid tone has been reported in the Yoruboid literature and previous accounts of tone behaviour in Iṣẹkírì suggest that a low tone is always deleted in favour of others at word boundary. However, synchronic data have shown that this is not the case. This paper investigates tonal asymmetry and the non-participation of the mid tone in some phonological processes in Iṣẹkírì. The study adopts an Optimality Theory (OT) version that incorporates the grounding conditions to develop constraints of implicational statements into faithfulness constraints. Data are elicited from eight speakers of the language, recordings are with the aid of a digital audio device and the tool used for our acoustic measurement is Praat 6.0.30. The analysis reveals that tonal asymmetry in this language always deletes the Mid-tone at word boundary and not the Low tone, also noting that the Low tone may be deleted in some cases. The lack of participation of the M tone in some phonological processes such as vowel elision, glide formation and vowel assimilation reveals the unstable nature of this tone in Iṣẹkírì. This paper concludes that the M tone is in asymmetry to the H and L tones in Iṣẹkírì and demonstrates the need for more perceptual and acoustic studies of tonal behaviour in Iṣẹkírì.