Shared Path: Unraveling Memorization in Multilingual LLMs through Language Similarities

Fuente: arXiv
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Main Authors: Luo, Xiaoyu, Chen, Yiyi, Bjerva, Johannes, Li, Qiongxiu
Format: Preprint
Published: 2025
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author Luo, Xiaoyu
Chen, Yiyi
Bjerva, Johannes
Li, Qiongxiu
author_facet Luo, Xiaoyu
Chen, Yiyi
Bjerva, Johannes
Li, Qiongxiu
contents We present the first comprehensive study of Memorization in Multilingual Large Language Models (MLLMs), analyzing 95 languages using models across diverse model scales, architectures, and memorization definitions. As MLLMs are increasingly deployed, understanding their memorization behavior has become critical. Yet prior work has focused primarily on monolingual models, leaving multilingual memorization underexplored, despite the inherently long-tailed nature of training corpora. We find that the prevailing assumption, that memorization is highly correlated with training data availability, fails to fully explain memorization patterns in MLLMs. We hypothesize that the conventional focus on monolingual settings, effectively treating languages in isolation, may obscure the true patterns of memorization. To address this, we propose a novel graph-based correlation metric that incorporates language similarity to analyze cross-lingual memorization. Our analysis reveals that among similar languages, those with fewer training tokens tend to exhibit higher memorization, a trend that only emerges when cross-lingual relationships are explicitly modeled. These findings underscore the importance of a \textit{language-aware} perspective in evaluating and mitigating memorization vulnerabilities in MLLMs. This also constitutes empirical evidence that language similarity both explains Memorization in MLLMs and underpins Cross-lingual Transferability, with broad implications for multilingual NLP.
format Preprint
id arxiv_https___arxiv_org_abs_2505_15722
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Shared Path: Unraveling Memorization in Multilingual LLMs through Language Similarities
Luo, Xiaoyu
Chen, Yiyi
Bjerva, Johannes
Li, Qiongxiu
Computation and Language
Artificial Intelligence
We present the first comprehensive study of Memorization in Multilingual Large Language Models (MLLMs), analyzing 95 languages using models across diverse model scales, architectures, and memorization definitions. As MLLMs are increasingly deployed, understanding their memorization behavior has become critical. Yet prior work has focused primarily on monolingual models, leaving multilingual memorization underexplored, despite the inherently long-tailed nature of training corpora. We find that the prevailing assumption, that memorization is highly correlated with training data availability, fails to fully explain memorization patterns in MLLMs. We hypothesize that the conventional focus on monolingual settings, effectively treating languages in isolation, may obscure the true patterns of memorization. To address this, we propose a novel graph-based correlation metric that incorporates language similarity to analyze cross-lingual memorization. Our analysis reveals that among similar languages, those with fewer training tokens tend to exhibit higher memorization, a trend that only emerges when cross-lingual relationships are explicitly modeled. These findings underscore the importance of a \textit{language-aware} perspective in evaluating and mitigating memorization vulnerabilities in MLLMs. This also constitutes empirical evidence that language similarity both explains Memorization in MLLMs and underpins Cross-lingual Transferability, with broad implications for multilingual NLP.
title Shared Path: Unraveling Memorization in Multilingual LLMs through Language Similarities
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2505.15722