The Realization of Low Tones in the Context of Downstep

Abstract

In this study, the pitch realization of low (L) tones in the context of downstep in Chinese is analyzed. The test sentences are composed of ‘High + Low + High + Low’ sequences, and the low point pitch of the L tones is investigated. It is found that there is an obvious downward trend for the L tones, that is, they always drop to a lower scale compared to the forgoing ones. Due to the final lowering effect, the degree of the last drop is always larger than the forgoing ones. When there are more downsteps, The initial L tone will be raised, but there is no significant variation for the final L tone. Introduction Downstep was originally observed in the tone languages in Africa, which refers to the stepwise lowering of High (H) tones in certain contexts [1]. In downstep, each successive H tone in longer downstepping sequences is lower than the preceding one, creating a cumulative ‘staircase’ pattern [2]. In tone languages, downstep is a common phenomenon, so speakers may employ ‘foresight’ in producing long downstepping sequences. Stewart [3] claimed that the pitch of H tones in downstepping sequences in Akan is sensitive to the number of following downsteps. He stated that the pitch of any particular high tone is raised by as many levels as there are downsteps in the subsequent part of the phrase, while the last H tone in the sequence tends to be realized at a constant level, its basic pitch. On the contrary, Schachter [4] maintained that the pitch of the first H tone in Akan is normally phonetically the same regardless of the number of the following downsteps, while later H tones descend to lower and lower values as the number of downsteps increases. In Chinese, there have been a number of studies related to tonal downstep. Xu [5] argued that anticipatory and carry-over tonal influences co-exist in Chinese, and they differ both in magnitude and in nature. Carry-over effects are mostly assimilatory: the starting F0 of a tone is assimilated to the offset value of a previous tone. Anticipatory effects, on the other hand, are mostly dissimilatory: a low onset value of a tone raises the maximum F0 value of a preceding tone. Shih [6] pointed out that the F0 contour of a Chinese utterance is affected by a number of factors, such as declination, downstep and final lowering, etc. Huang et al. [7] examined downstep in Chinese by subtly designed sentences. It is found that, when there is intervening low tone, it will compress the pitch range of the following syllable. It is the top line that is mainly affected, and the bottom line keeps unaffected. When there is no intervening low tone, the top line of the intonational phrase is realized in a linear downward trend. The experiment reported here will investigate the pitch values of utterances with 2 to 5 HL sequences, i.e. utterances with 4 to 10 syllables, and the aim is to find out the pitch realization of L tones in the context of downstep.