Combining Discriminative Feature, Transform, and Model Training for Large Vocabulary Speech Recognition

Recent developments in large vocabulary continuous speech recognition (LVCSR) have shown the effectiveness of discriminative training approaches, employing the following three representative techniques: discriminative Gaussian training using the minimum phone error (MPE) criterion, discriminately trained features estimated by multilayer perceptrons (MLPs); and discriminative feature transforms such as feature-level MPE (fMPE). Although MLP features, MPE models, and fMPE transforms have each been shown to improve recognition accuracy, no previous work has applied all three in a single LVCSR system. This paper uses a state-of-the-art Mandarin recognition system as a platform to study the interaction of all three techniques. Experiments in the broadcast news and broadcast conversation domains show that the contribution of each technique is nonredundant, and that the full combination yields the best performance and has good domain generalization.