2016 年 20 巻 3 号 p. 46-65
The Ikema dialect of Miyako, Southern Ryukyuan, has a three-pattern accent system in which three tone classes (Types A, B, and C) are lexically contrastive, although the Type A simplex nouns are fewer. The biased distribution of tone classes is a consequence of the diachronic change, whereby Types A and B are merged together. This study aims to confirm that the three-pattern system in Ikema retains the proto-Ryukyuan system and to demonstrate that a set of words that are originally of Type A and share specific meanings are not merged into Type B.