Automatic detection of vowel pronunciation errors using multiple information sources

Frequent pronunciation errors made by L2 learners of Dutch often concern vowel substitutions. To detect such pronunciation errors, ASR-based confidence measures (CMs) are generally used. In the current paper we compare and combine confidence measures with MFCCs and phonetic features. The results show that the best results are obtained by using MFCCs, then CMs, and finally phonetic features, and that substantial improvements can be obtained by combining different features.