The effort is started by the establishment of a tonal data pool of 57 typical registral-tonal southern dialects. Five dimensions—tonal category, pitch contour, register, pitch value and duration—are digitalized and considered together as the main influential factors of the configuration of tonal structure. With the help of this data pool, we can observe more closely and directly how linguistic targets of different dimensions support, enhance, compete with each other, or establish historical relations backwards. They provide with us the typological knowledge of correlation between five dimensions and further support for historical reconstructions.
Based on these registral-tonal southern dialects, we conclude five tonal evolution patterns based on different phonation backgrounds. There is the Cixi 慈溪 pattern driven purely according to phonation conditions. There is the Wenzhou 溫州 pattern shows how a pure slack phonation background, collaborated with high-pitched or tense/ falsetto conditions, can provide circumstances for transference of sonorant-initial syllables from Yang
陽 tones (B tones) to Yin
陰 tones (A tones), which is almost the very type we hope to find to support the historical Zhuoshang Bian Qu
濁上變去 problem. The rest three types are different stages of a continuum of the degree of muddiness of a mixture of slack phonation and model-voiced phonation. We see that the pattern and activeness of tonal switch, merger and splitting are highly relevant to the degree of complicity and the intensity of the muddiness of the phonation background, and the relevant tones will exchange syllables by condition of initial types in a bundled and complementary way. We also find that the merger and splitting are more active at the higher pitch range.
The solving of the historical problem of Zhuoshang Bian Qu
濁上變去 gives us a good example of how factors of the phonation dimension and the pitch dimension correlate and cooperate to promote a complicated tonal evolution. The whole problem is divided into two separated parts: First, the switch and merger of tone2b-s to tone2a; second, the merger of tone2b-o to tone3. Every part is further divided into several steps. Every step shows either the conflict of different phonation types within a single syllable, or competition of linguistic targets of different dimensions for the tonal distinctive feature, or multi-variations caused by complicated phonations and extreme pitch heights.
Taking all the typological, phonological and historical aspects together, we argue that for registral-tonal languages like the Early Middle Chinese and Chinese dialects in southern Wu 吳, some Xiang 湘and Gan 贛, the tonal structure should be understood from a multi-dimensional perspective, and the cause of many of the tonal evolution should be traced back to the origin of the interaction and correlation relationship between pitch and phonation.