The phonological status of Low tones in Shanghai tone sandhi

In Shanghai tone sandhi, with the exception of T5 (yangru) sandhi, a pitch-fall occurs at the second or third syllable of a phonological word (or a sandhi domain). Previous analyses argue that this is invoked by the insertion of a default Low tone to satisfy the Well-formedness Condition of the autosegmental theory. However, in the framework of the present autosegmental theory, that condition is no longer necessarily satisfied, and an alternative interpretation, adopting a boundary Low tone, has been suggested. To evaluate the appropriateness of the default and boundary interpretations, we compared pitch contours among di- to tetrasyllabic words in greater detail. The results show that, in T1 to T4 sandhi, disyllabic words tend to have lower pitch contours than tri- and tetrasyllabic words at the first and second syllables, and that, in tetrasyllables, minimum pitch values were constantly attested at the third syllable. These results indicate that in Shanghai tone sandhi, a boundary Low tone is assigned at the right edge of a phonological word, and it is further associated with the third syllable in tetrasyllables. This boundary interpretation further gives an appropriate explanation of the difference of the pitch-fall between Middle and New Shanghai.