If they've got low-level control of the synthesized voice frequency, it shouldn't be terribly difficult for Dynavox to create a musical pitch contour to drive the voice.

Sinsy appears to be owned by the HTS (HMM-based Speech Synthesis System) working group. It looks like they license their tools under a Modified BSD License, which is very cool.

There are a number of interesting text-to-speech tools that use HMMs (Hidden Markov Models), but singing creates an additional complexity of creating an adequately large corpus of training data. The only paper I've been able to find on Sinsy is 99% Japanese, and Google's translation is a bit of a mess, but it notes because parts of Sinsy use the HTK license, commercial use is prohibited. So I guess we don't need to worry about it being bought out by a company.

That also explains why the paper I referenced focused on converting speech into singing.

-- David Cuny
My virtual singer development blog

Vocal control, you say. Never heard of it. Is that some kind of ProTools thing?