INTERSPEECH 2008
9th Annual Conference of the International Speech Communication Association

Brisbane, Australia
September 22-26, 2008

Comparison of Variable Selection Methods and Classifiers for Native Accent Identification

Tingyao Wu, Peter Karsmakers, Hugo Van hamme, Dirk Van Compernolle

Katholieke Universiteit Leuven, Belgium

Acoustic differences are so subtle in a native accent identification (AID) task that a brute force frame-based Gaussian Mixture Model (GMM) fails to discover the tiny distinctions [1]. Apart from the frame-based framework, in this paper we propose a vector-based speaker modeling method, to which common support vector machine (SVM) kernels can be applied. The vector-based speaker model is composed of the concatenation of the average acoustic representations of all phonemes. SVM and GMM classifiers are compared on the speaker models. Moreover, based on the observation that accents only differ in a limited number of phonemes, a variable selection framework is indispensable to select accent relevant features. We investigate a forward selection method, Analysis of Variance (ANOVA) , and a backward selection method, SVM- Recursive Feature Elimination (SVM-RFE). We find that the multiclass SVM-RFE achieves comparable performance with the ANOVA on optimally selected variable sets, while it obtains excellent performance with very few features in low dimensions. Results demonstrate the effectiveness of the proposed speaker models together with the SVM classifier both in low dimensions and in high dimensions as well as the necessity of variable selection.

Reference

  1. J-P. Martens, "Improving the discrimination between native accents when recorded over different channels," in InterSpeech, Lisbon, Portugal, Sept 2005, pp. 2821-2824. (ISCA Archive, http://www.isca-speech.org/archive/interspeech_2005)

Full Paper

Bibliographic reference.  Wu, Tingyao / Karsmakers, Peter / Van hamme, Hugo / Compernolle, Dirk Van (2008): "Comparison of variable selection methods and classifiers for native accent identification", In INTERSPEECH-2008, 305-308.