Pseudo2Real: Task Arithmetic for Pseudo-Label Correction in Automatic Speech Recognition

Yi-Cheng Lin, Yu-Hsuan Li Liang, Hsuan Su, Tzu-Quan Lin, Shang-Tse Chen, Yun-Nung Chen, Hung-yi Lee


Abstract
Robust ASR under domain shift is crucial because real-world systems encounter unseen accents and domains with limited labeled data. Although pseudo-labeling offers a practical workaround, it often introduces systematic, accent-specific errors that filtering fails to fix. We ask: How can we correct these recurring biases without target ground truth? We propose a simple parameter-space correction: in a source domain containing both real and pseudo-labeled data, two ASR models are fine-tuned from the same initialization, one on ground-truth labels and the other on pseudo-labels, and their weight difference forms a correction vector that captures pseudo-label biases.When applied to a pseudo-labeled target model, this vector enhances recognition, achieving up to a 35% relative Word Error Rate (WER) reduction on AfriSpeech-200 across ten African accents with the Whisper tiny model.
Anthology ID:
2026.findings-acl.59
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
Findings
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Publisher:
Association for Computational Linguistics
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Pages:
1160–1175
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URL:
https://preview.aclanthology.org/ingest-acl/2026.findings-acl.59/
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Cite (ACL):
Yi-Cheng Lin, Yu-Hsuan Li Liang, Hsuan Su, Tzu-Quan Lin, Shang-Tse Chen, Yun-Nung Chen, and Hung-yi Lee. 2026. Pseudo2Real: Task Arithmetic for Pseudo-Label Correction in Automatic Speech Recognition. In Findings of the Association for Computational Linguistics: ACL 2026, pages 1160–1175, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Pseudo2Real: Task Arithmetic for Pseudo-Label Correction in Automatic Speech Recognition (Lin et al., Findings 2026)
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