Traditional phonetics predominately believes that the laws to modify tone of the three-word phrases in falling-rising tone are not complex but simple ones.

The phonological analysis shows that the same markedness constraint holds true both in tone sandhi and neutral tones in trisyllabic sequence,which supports the hypothesis that tone sandhi and neutral tones are corr.

Based on the corpus of published representative dialects (including a total of 300 recorded dialects, one of them from my dialect), this paper sorts out the evolution of the rising-tone medieval characters in modern dialects, sums up a number of types, and explores the development characteristics and reasons for changes of the rising-tone medieval characters in modern dialects.

Within the OT framework,the paper analyzes the tone sandhi of trisyllabic sequences in Tianjin dialect,claiming that the parallelist OT can provide a satisfactory solution to the paradoxical problem of Tianjin tone san.

The tone sandhi in trisyllabic sequences in Tianjin(天津)dialect,called the paradox of Tianjin(天津)tone sandhi,has received great attention The tone sandhi in trisyllabic sequences in Tianjin(天津)dialect is analyzed within classic OT,which also shows that OT can provide a satisfactory solution to the metrically conditioned tone sandhi.