Ternary or three-level vowel length is typologically rare, and supporting evidence is limited. This paper presents the results of an investigation into the hypothesised case of this configuration in Shilluk. We first describe the role of vowel length in Shilluk phonology and morphology, and then report on an acoustic study in which minimal sets for vowel length (short, long, overlong) are measured for vowel duration, coda duration, vowel quality and fundamental frequency. Short, long and overlong vowels differ significantly and substantially in terms of vowel duration: 96% of the items can be classified successfully for vowel length on the basis of this measurement alone. Of the other measurements, only vowel quality is significant, and this effect is considerably smaller. The mean values for vowel duration – 68, 111 and 150 ms for short, long and overlong vowels respectively – are similar to those reported for ternary vowel length in Dinka.

中文翻译：

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Shilluk 中的三元元音长度

三元或三级元音长度在类型学上很少见，支持证据有限。本文介绍了对 Shilluk 中这种配置的假设案例的调查结果。我们首先描述了元音长度在 Shilluk 音韵学和形态学中的作用，然后报告了一项声学研究，其中测量了元音长度（短、长、超长）的最小集合，用于测量元音持续时间、尾音持续时间、元音质量和基本频率。短元音、长元音和超长元音在元音持续时间方面存在显着差异：仅根据这一测量，就可以成功地将 96% 的项目分类为元音长度。在其他测量中，只有元音质量很重要，而且这种影响要小得多。元音持续时间的平均值——简称为 68、111 和 150 毫秒，