Estimation of speech formant-dynamics using neural networks

Formant Dynamics is an interesting research field in Speech Perception, Speech Parameterizacion, Synthesis, and Recognition. The Spectrogram shown in Fig. 1.a, corresponding to the utterance “I wished you were here a year ago” reveals important dynamic changes in the positions of the poles in the Transfer Function of the Vocal Tract with time. In the associated template shown in Fig. 1.b, the set of PARCOR parameters generating the Spectrogram may be seen. As it could be expected, the changes in the Spectrogram are related with changes in the PARCORgram. In many applications, such as Phone Labelling [Robinson.94], or Formant Tracing [Nagayama.94], it should be desirable to detect the set of Vector Parameters responsible for these changes, or to inferr Formant Dynamics from Vector Parameters. Through the present work one such application using Gradient-Adaptive Lattices and Time-Delay Neural Networks will be described.