One-Class SVMs Based Pronunciation Verification Approach

The automatic assessment of speech plays an important role in Computer Aided Pronunciation Learning systems. However, modeling both the correct and incorrect pronunciation of each phoneme to achieve accurate pronunciation verification is unfeasible due to the lack of sufficient mispronounced samples in training datasets. In this paper, we propose a novel approach that handles this unbalanced data distribution by building multiple one-class SVMs to evaluate each phoneme as correct or incorrect. We model the correct pronunciation of each individual phoneme with a one-class SVM trained using a set of speech attributes features, namely the manner and place of articulation. These features are extracted from a bank of pre-trained DNN speech attributes classifiers. The one-class SVM model measures the similarity between the new data and the training set and then classifies it as normal (correct) or an anomaly (incorrect). We evaluated the system using native speech corpus and disordered speech corpus and compared it with the conventional Goodness of Pronunciation (GOP) algorithm. The results show that our approach reduces the false-acceptance and false-rejection rates by around 26% and 39% respectively.