Improving TTS for Shanghainese: Addressing Tone Sandhi via Word
  Segmentation
Yuanhao Chen
Tone is a crucial component of the prosody of Shanghainese, a Wu Chinese
variety spoken primarily in urban Shanghai. Tone sandhi, which applies to all
multi-syllabic words in Shanghainese, then, is key to natural-sounding speech.
Unfortunately, recent work on Shanghainese TTS (text-to-speech) such as Apple's
VoiceOver has shown poor performance with tone sandhi, especially LD
(left-dominant sandhi). Here I show that word segmentation during text
preprocessing can improve the quality of tone sandhi production in TTS models.
Syllables within the same word are annotated with a special symbol, which
serves as a proxy for prosodic information of the domain of LD. Contrary to the
common practice of using prosodic annotation mainly for static pauses, this
paper demonstrates that prosodic annotation can also be applied to dynamic
tonal phenomena. I anticipate this project to be a starting point for bringing
formal linguistic accounts of Shanghainese into computational projects. Too
long have we been using the Mandarin models to approximate Shanghainese, but it
is a different language with its own linguistic features, and its digitisation
and revitalisation should be treated as such.