arXiv Computation and Language By Nguyen Minh Chi, Mo El-Haj, Nguyen Ha Thanh, Dawn Knight, Paul Rayson

Cross-Lingual Legal QA for Vietnamese Labour Law: Retrieval, Translation, and Verifier-Guided Correction

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The paper presents a cross‑lingual legal QA system for Vietnamese labour law, introducing a bilingual evaluation suite of 231 Vietnamese–English question–answer pairs, 75 of which are annotated for five complex legal reasoning phenomena. It evaluates a verifier‑guided pipeline that decomposes answers into claims, checks citation reachability and entailment, and corrects citation failures and contradictions, and introduces six automatic diagnostics for faithfulness to retrieved evidence. Experiments show that dense retrieval outperforms sparse and hybrid retrieval, translation placement has no significant effect on diagnostics, and verifier‑guided correction modestly improves citation preservation but not other dimensions, with human evaluation indicating a gap between automatic diagnostics and human judgments.

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