Semi-supervised Learning For Robust Speech Evaluation

Fuente: arXiv
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Main Authors: Zhang, Huayun, Wong, Jeremy H. M., Lin, Geyu, Chen, Nancy F.
Format: Preprint
Published: 2024
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author Zhang, Huayun
Wong, Jeremy H. M.
Lin, Geyu
Chen, Nancy F.
author_facet Zhang, Huayun
Wong, Jeremy H. M.
Lin, Geyu
Chen, Nancy F.
contents Speech evaluation measures a learners oral proficiency using automatic models. Corpora for training such models often pose sparsity challenges given that there often is limited scored data from teachers, in addition to the score distribution across proficiency levels being often imbalanced among student cohorts. Automatic scoring is thus not robust when faced with under-represented samples or out-of-distribution samples, which inevitably exist in real-world deployment scenarios. This paper proposes to address such challenges by exploiting semi-supervised pre-training and objective regularization to approximate subjective evaluation criteria. In particular, normalized mutual information is used to quantify the speech characteristics from the learner and the reference. An anchor model is trained using pseudo labels to predict the correctness of pronunciation. An interpolated loss function is proposed to minimize not only the prediction error with respect to ground-truth scores but also the divergence between two probability distributions estimated by the speech evaluation model and the anchor model. Compared to other state-of-the-art methods on a public data-set, this approach not only achieves high performance while evaluating the entire test-set as a whole, but also brings the most evenly distributed prediction error across distinct proficiency levels. Furthermore, empirical results show the model accuracy on out-of-distribution data also compares favorably with competitive baselines.
format Preprint
id arxiv_https___arxiv_org_abs_2409_14666
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Semi-supervised Learning For Robust Speech Evaluation
Zhang, Huayun
Wong, Jeremy H. M.
Lin, Geyu
Chen, Nancy F.
Artificial Intelligence
Speech evaluation measures a learners oral proficiency using automatic models. Corpora for training such models often pose sparsity challenges given that there often is limited scored data from teachers, in addition to the score distribution across proficiency levels being often imbalanced among student cohorts. Automatic scoring is thus not robust when faced with under-represented samples or out-of-distribution samples, which inevitably exist in real-world deployment scenarios. This paper proposes to address such challenges by exploiting semi-supervised pre-training and objective regularization to approximate subjective evaluation criteria. In particular, normalized mutual information is used to quantify the speech characteristics from the learner and the reference. An anchor model is trained using pseudo labels to predict the correctness of pronunciation. An interpolated loss function is proposed to minimize not only the prediction error with respect to ground-truth scores but also the divergence between two probability distributions estimated by the speech evaluation model and the anchor model. Compared to other state-of-the-art methods on a public data-set, this approach not only achieves high performance while evaluating the entire test-set as a whole, but also brings the most evenly distributed prediction error across distinct proficiency levels. Furthermore, empirical results show the model accuracy on out-of-distribution data also compares favorably with competitive baselines.
title Semi-supervised Learning For Robust Speech Evaluation
topic Artificial Intelligence
url https://arxiv.org/abs/2409.14666