Tonal neutralization in the Ikema dialect of Miyako Ryukyuan

The Ikema dialect of Miyako Ryukyuan (henceforth Ikema) has three lexically contrastive tone classes. Ikema exhibits widespread tonal neutralization such that the three-way contrast can only be observed in quite restricted contexts. The goals of this article are to determine the prosodic conditions that bring about tonal neutralization in Ikema and to make generalizations about surface pitch patterning in utterances. Involved in the neutralization is the hierarchical prosodic structure with three prosodic constituents above the mora, that is, the foot, Prosodic Word, and Clitic Group. The three-way tonal contrast in Ikema is fully realized (and hence not neutralized) when the following two conditions are met. Firstly, the utterance as a whole consists of at least three Prosodic Words. Secondly, the Clitic Group consists of at least two Prosodic Words. Moreover, long utterances can exhibit pitch patterns resulting from the Principle of Rhythmic Alternation. The rhythmic alternation can also trigger tonal neutralization in some cases.