Structure-dependent tone sandhi in real and nonce disyllables in Shanghai Wu

Disyllabic sequences in Shanghai Wu undergo different types of tone sandhi depending on their structure: phonological words (e.g., modifier-nouns) spread the initial tone across the disyllable, while phrases (e.g., non-lexicalized verb-nouns) maintain the final tone and level the contour of the nonfinal tone. We investigated the productivity of the two tone sandhi types through 48 speakers' productions of real and nonce disyllables. Our results show that (a) the word-level tone sandhi in Shanghai indeed involves tone spreading, while the phrase-level sandhi is better interpreted as phonetic contour reduction, (b) the spreading sandhi generally applies productively to nonce words, but there are some differences in tone production between real and nonce words that are attributable to both categorical non-application and gradient application of the sandhi in nonce words, and (c) the structure dependency of Shanghai tone sandhi is also productive, as the speakers produced qualitatively different f0 patterns in modifier-noun nonce words and verb-noun nonce phrases. These results indicate that in order to arrive at a full picture of tone sandhi patterning, experimental data that shed light on the generalizations that speakers make from the speech input are necessary.