AP-GRPO: Anchor-Gated Phonetic Alignment with Policy Optimization for Pathological Speech Reconstruction

Pengfei Zhang, Hoang H Nguyen, Yutong Song, Wenjun Huang, Tahmid Imtiaz Imu, Henry Peng Zou, Jiang Wu, Honghui Xu, Amir M. Rahmani


Abstract
Pathological speech from patients with neurodegenerative and neuromotor disorders is often acoustically distorted and linguistically fragmented, making pathological speech reconstruction necessary to recover intended textual content from distorted and incomplete speech recordings. Crucially, such recordings are rarely uniformly degraded: some words or short phrases remain reliable and can serve as audible anchors for reconstructing the corrupted surrounding content. We introduce **Anchor-gated Phonetic Group Relative Policy Optimization (AP-GRPO)**, a GRPO framework with phonetic reward that aligns speech language models (SLMs) through audible-anchor preservation and inter-anchor phonetic compatibility to the original speech signal. AP-GRPO consists of: (i) an **anchor-gated reward** that matches reliable audible anchors in clear regions; and (ii) an **inter-anchor phonetic alignment reward** that evaluates whether recovered contents are phonetically supported by the corresponding corrupted inter-anchor speech span. Across four disease conditions, AP-GRPO improves faithful speech reconstruction, and the learned anchor constraint automatically adapts to each condition and thus reveals interpretable disease-specific profiles: conditions with severe articulatory degradation require stronger anchor enforcement, whereas milder impairment or linguistically impaired conditions rely more on phonetic alignment for inter-anchor recovery.
Anthology ID:
2026.emnlp-main.1287
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
29320–29340
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URL:
https://aclanthology.org/2026.emnlp-main.1287/
DOI:
Bibkey:
Cite (ACL):
Pengfei Zhang, Hoang H Nguyen, Yutong Song, Wenjun Huang, Tahmid Imtiaz Imu, Henry Peng Zou, Jiang Wu, Honghui Xu, and Amir M. Rahmani. 2026. AP-GRPO: Anchor-Gated Phonetic Alignment with Policy Optimization for Pathological Speech Reconstruction. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 29320–29340, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
AP-GRPO: Anchor-Gated Phonetic Alignment with Policy Optimization for Pathological Speech Reconstruction (Zhang et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1287.pdf