Mitigating Negative Interference in Multilingual Knowledge Editing through Null-Space Constraints

Wei Sun, Tingyu Qu, Mingxiao Li, Jesse Davis, Marie-Francine Moens


Abstract
Efficiently updating multilingual knowledge in large language models (LLMs) without disrupting coherent factual representations across languages remains a significant challenge. While deploying separate editing systems for each language might seem viable, this approach incurs substantial costs due to the need to manage multiple models. A more efficient solution involves integrating knowledge updates across all languages into a unified model. However, sequential edits across languages often lead to destructive parameter interference, significantly degrading multilingual generalization and the accuracy of injected knowledge. To address this issue, we propose LangEdit, a novel null-space constrained framework designed to precisely isolate language-specific knowledge updates. The core innovation of LangEdit lies in its ability to project parameter updates for each language onto the orthogonal complement of other languages’ subspaces. This approach mathematically guarantees update independence while preserving multilingual generalization capabilities. We conduct a comprehensive evaluation across three model architectures, six languages, and four downstream tasks, demonstrating that LangEdit effectively mitigates parameter interference and outperforms existing state-of-the-art editing methods. Our results highlight its potential for enabling efficient and accurate multilingual knowledge updates in LLMs.
Anthology ID:
2025.findings-acl.460
Volume:
Findings of the Association for Computational Linguistics: ACL 2025
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Wanxiang Che, Joyce Nabende, Ekaterina Shutova, Mohammad Taher Pilehvar
Venues:
Findings | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
8796–8810
Language:
URL:
https://preview.aclanthology.org/acl25-workshop-ingestion/2025.findings-acl.460/
DOI:
Bibkey:
Cite (ACL):
Wei Sun, Tingyu Qu, Mingxiao Li, Jesse Davis, and Marie-Francine Moens. 2025. Mitigating Negative Interference in Multilingual Knowledge Editing through Null-Space Constraints. In Findings of the Association for Computational Linguistics: ACL 2025, pages 8796–8810, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
Mitigating Negative Interference in Multilingual Knowledge Editing through Null-Space Constraints (Sun et al., Findings 2025)
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PDF:
https://preview.aclanthology.org/acl25-workshop-ingestion/2025.findings-acl.460.pdf