Contrastive tonal alignment in falling contours in Shilluk

It is widely assumed that tonal alignment is not contrastive in contour tones (Hyman 1988, Odden 1995, Silverman 1997, Yip 2002, Xu 2005, Xu & Liu 2006). However, evidence suggesting that such contrasts are possible has recently been reported ([authors], DiCanio 2014). In relation to this controversy, this paper reports on an acoustic analysis of the tone system of Shilluk. The dataset is built around the contrast of Low vs. Early-aligned High Fall vs. Late-aligned High Fall vs. High, in closed monosyllabic stems with a short vowel. The results support the hypothesis that tonal alignment is indeed contrastive in falling contour tones in the surface phonology of Shilluk: the two falling contours differ in terms of tonal alignment, relative to one another, and also relative to phonetically similar configurations composed of level tones. In contrast, other phonetic parameters (f0 height, size of f0 change, duration) are not significant.