CC-Tuning: A Cross-Lingual Connection Mechanism for Improving Joint Multilingual Supervised Fine-Tuning

Fuente: arXiv
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Main Authors: Ye, Yangfan, Feng, Xiaocheng, Yuan, Zekun, Feng, Xiachong, Qin, Libo, Huang, Lei, Ma, Weitao, Huang, Yichong, Zhang, Zhirui, Lu, Yunfei, Yan, Xiaohui, Tang, Duyu, Tu, Dandan, Qin, Bing
Format: Preprint
Published: 2025
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author Ye, Yangfan
Feng, Xiaocheng
Yuan, Zekun
Feng, Xiachong
Qin, Libo
Huang, Lei
Ma, Weitao
Huang, Yichong
Zhang, Zhirui
Lu, Yunfei
Yan, Xiaohui
Tang, Duyu
Tu, Dandan
Qin, Bing
author_facet Ye, Yangfan
Feng, Xiaocheng
Yuan, Zekun
Feng, Xiachong
Qin, Libo
Huang, Lei
Ma, Weitao
Huang, Yichong
Zhang, Zhirui
Lu, Yunfei
Yan, Xiaohui
Tang, Duyu
Tu, Dandan
Qin, Bing
contents Current large language models (LLMs) often exhibit imbalanced multilingual capabilities due to their English-centric training corpora. To address this, existing fine-tuning approaches operating at the data-level (e.g., through data augmentation or distillation) typically introduce implicit cross-lingual alignment, overlooking the potential for more profound, latent-level cross-lingual interactions. In this work, we propose CC-Tuning, a novel multilingual fine-tuning paradigm that explicitly establishes a cross-lingual connection mechanism at the latent level. During training, CC-Tuning fuses the feed forward activations from both English and non-English inputs, enabling the model to benefit from both linguistic resources. This process is facilitated with a trainable Decision Maker that identifies beneficial activations. Furthermore, during inference, a Transform Matrix is utilized to simulate the cross-lingual connection under monolingual setting through representation transformation. Our experiments on six benchmarks covering 22 languages show that CC-Tuning outperforms vanilla SFT and offers a strong latent-level alternative to data-level augmentation methods. Further analysis also highlights the practicality of CC-Tuning and the potential of latent-level cross-lingual interactions in advancing the multilingual performance of LLMs.
format Preprint
id arxiv_https___arxiv_org_abs_2506_00875
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle CC-Tuning: A Cross-Lingual Connection Mechanism for Improving Joint Multilingual Supervised Fine-Tuning
Ye, Yangfan
Feng, Xiaocheng
Yuan, Zekun
Feng, Xiachong
Qin, Libo
Huang, Lei
Ma, Weitao
Huang, Yichong
Zhang, Zhirui
Lu, Yunfei
Yan, Xiaohui
Tang, Duyu
Tu, Dandan
Qin, Bing
Computation and Language
Current large language models (LLMs) often exhibit imbalanced multilingual capabilities due to their English-centric training corpora. To address this, existing fine-tuning approaches operating at the data-level (e.g., through data augmentation or distillation) typically introduce implicit cross-lingual alignment, overlooking the potential for more profound, latent-level cross-lingual interactions. In this work, we propose CC-Tuning, a novel multilingual fine-tuning paradigm that explicitly establishes a cross-lingual connection mechanism at the latent level. During training, CC-Tuning fuses the feed forward activations from both English and non-English inputs, enabling the model to benefit from both linguistic resources. This process is facilitated with a trainable Decision Maker that identifies beneficial activations. Furthermore, during inference, a Transform Matrix is utilized to simulate the cross-lingual connection under monolingual setting through representation transformation. Our experiments on six benchmarks covering 22 languages show that CC-Tuning outperforms vanilla SFT and offers a strong latent-level alternative to data-level augmentation methods. Further analysis also highlights the practicality of CC-Tuning and the potential of latent-level cross-lingual interactions in advancing the multilingual performance of LLMs.
title CC-Tuning: A Cross-Lingual Connection Mechanism for Improving Joint Multilingual Supervised Fine-Tuning
topic Computation and Language
url https://arxiv.org/abs/2506.00875