dorsal/arxiv
View SchemaEvaluating Cross-Lingual Unlearning in Multilingual Language Models
| Authors | Tyler Lizzo, Larry Heck |
|---|---|
| Categories | |
| ArXiv ID | 2601.06675vv1 |
| URL | https://arxiv.org/abs/2601.06675 |
| License | http://creativecommons.org/licenses/by/4.0/ |
Abstract
We present the first comprehensive evaluation of cross-lingual unlearning in multilingual LLMs. Using translated TOFU benchmarks in seven language/script variants, we test major unlearning algorithms and show that most fail to remove facts outside the training language, even when utility remains high. However, subspace-projection consistently outperforms the other methods, achieving strong cross-lingual forgetting with minimal degradation. Analysis of learned task subspaces reveals a shared interlingua structure: removing this shared subspace harms all languages, while removing language-specific components selectively affects one. These results demonstrate that multilingual forgetting depends on geometry in weight space, motivating subspace-based approaches for future unlearning systems.
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"abstract": "We present the first comprehensive evaluation of cross-lingual unlearning in multilingual LLMs. Using translated TOFU benchmarks in seven language/script variants, we test major unlearning algorithms and show that most fail to remove facts outside the training language, even when utility remains high. However, subspace-projection consistently outperforms the other methods, achieving strong cross-lingual forgetting with minimal degradation. Analysis of learned task subspaces reveals a shared interlingua structure: removing this shared subspace harms all languages, while removing language-specific components selectively affects one. These results demonstrate that multilingual forgetting depends on geometry in weight space, motivating subspace-based approaches for future unlearning systems.",
"arxiv_id": "2601.06675",
"authors": [
"Tyler Lizzo",
"Larry Heck"
],
"categories": [
"cs.CL"
],
"license": "http://creativecommons.org/licenses/by/4.0/",
"title": "Evaluating Cross-Lingual Unlearning in Multilingual Language Models",
"url": "https://arxiv.org/abs/2601.06675",
"version": "v1"
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