Intelligibility training for foreign-accented speech: A preliminary study

Abstract

A computer-based speech training system, the Indiana Speech Training Aid (ISTRA), has been shown to be clinically effective for improving the speech of hearing-impaired and phonologically disordered individuals [Kewley-Port etal., Clin. Ling. Phon. 5, 13–38 (1991)]. The potential value of speech recognition technology for the training of foreign-accented speech, using an overall measure of speech quality as feedback, was assessed. Phonological errors in English spoken by two native Mandarin speakers were analyzed and several training targets selected. One consonant and one vowel contrast each were selected for training using ISTRA, and by a speech-language pathologist (SLP). Pre- and posttraining tokens were rated for quality by a listener jury. Results showed significant improvement for both the ISTRA-trained consonant /l/, and the SLP-trained consonant /θ/. However, only one of the two vowel contrasts for each speaker improved significantly. ISTRA-trained sounds which showed significant improvement did so for both trained and untrained words. Two untrained phonemes, /r/ and /U/, also improved significantly, possibly indicating a generalization of improved sounds to other phonological distinctions in English. These results are promising as regards the usefulness of speech recognition technology for pronunciation training. [Work supported by NIHDCD SBIR Program.]