Optimizing Automatic Speech Recognition for Low-Proficient Non-Native Speakers. (1st November 2009)

• Record Type: Journal Article
• Authors: van Doremalen, Joost; Cucchiarini, Catia; Strik, Helmer
• Other Names: Stemmer Georg Academic Editor.
• Is Part Of: EURASIP journal on audio, speech, and music processing. Volume 2010(2010)
• Publication Date: 2009-11-01
• Subjects: Sound -- Recording and reproducing -- Digital techniques -- Periodicals; Computer sound processing -- Periodicals; Computer sound processing; Sound -- Recording and reproducing -- Digital techniques; Periodicals; Electronic journal; Electronic journals; 620.2
• DOI: 10.1155/2010/973954
• Languages: English
• ISSNs: 1687-4714

Abstract

Abstract : Computer-Assisted Language Learning (CALL) applications for improving the oral skills of low-proficient learners have to cope with non-native speech that is particularly challenging. Since unconstrained non-native ASR is still problematic, a possible solution is to elicit constrained responses from the learners. In this paper, we describe experiments aimed at selecting utterances from lists of responses. The first experiment on utterance selection indicates that the decoding process can be improved by optimizing the language model and the acoustic models, thus reducing the utterance error rate from 29–26% to 10–8%. Since giving feedback on incorrectly recognized utterances is confusing, we verify the correctness of the utterance before providing feedback. The results of the second experiment on utterance verification indicate that combining duration-related features with a likelihood ratio (LR) yield an equal error rate (EER) of 10.3%, which is significantly better than the EER for the other measures in isolation.