Speech Prosody 2008
This study revisits the phonetics and phonology of Shanghai tone sandhi by examining the f0 contours of non-initial syllables within sandhi domains which start with different lexical tones. Results show significant f0 variation due to the initial lexical tones; the variation, however, diminishes as the number of non-initial syllables increases, resulting in near convergence of f0 values by the end of the 3rd syllable. This suggests the existence of a low tone target for non-initial syllables, the phonetic implementation of which is weak and remarkably comparable to the neutral tone in Standard Chinese . Shanghai Chinese thus suggests the possible existence of weak-strong tonal contrast, like the neutral vs. lexical tonal contrast in Standard Chinese, which manifests at a prosodic level higher than syllable.
Bibliographic reference. Chen, Yiya (2008): "Revisiting the phonetics and phonology of Shanghai tone sandhi", In SP-2008, 253-256.