This is an overview of approaches to automatically reduce the intra and inter speaker variability in the speech signal. Attention is focussed on particular methods to adapt standard Automatic Speech Recognizers (ASR) to new users, taking into account their specific acoustical characteristics. Speaker normalization and adaptation techniques for a template-based recognizers are described. They are
... [Show full abstract] based on spectral normalization, on the learning of spectral transformations and on code book substitution for VQ front end.