  While neural networks have been employed to handle several different
text-to-speech tasks, ours is the first system to use neural networks
throughout, for both linguistic and acoustic processing. We divide the
text-to-speech task into three subtasks, a linguistic module mapping from text
to a linguistic representation, an acoustic module mapping from the linguistic
representation to speech, and a video module mapping from the linguistic
representation to animated images. The linguistic module employs a
letter-to-sound neural network and a postlexical neural network. The acoustic
module employs a duration neural network and a phonetic neural network. The
visual neural network is employed in parallel to the acoustic module to drive a
talking head. The use of neural networks that can be retrained on the
characteristics of different voices and languages affords our system a degree
of adaptability and naturalness heretofore unavailable.
