Semantic Aware Linear Transfer by Recycling Pre-trained Language Models for Cross-lingual Transfer

Seungyoon Lee, Seongtae Hong, Hyeonseok Moon, Heuiseok Lim


Abstract
Large Language Models (LLMs) are increasingly incorporating multilingual capabilities, fueling the demand to transfer them into target language-specific models. However, most approaches, which blend the source model’s embedding by replacing the source vocabulary with the target language-specific vocabulary, may constrain expressive capacity in the target language since the source model is predominantly trained on English data. In this paper, we propose Semantic Aware Linear Transfer (SALT), a novel cross-lingual transfer technique that recycles embeddings from target language Pre-trained Language Models (PLMs) to transmit the deep representational strengths of PLM-derived embedding to LLMs. SALT derives unique regression lines based on the similarity in the overlap of the source and target vocabularies to handle each non-overlapping token’s embedding space. Our extensive experiments show that SALT significantly outperforms other transfer methods, achieving lower loss and faster convergence during language adaptation. Notably, SALT achieves remarkable performance in cross-lingual understanding setups compared to other methods. Furthermore, we highlight the scalable use of PLMs to enhance the functionality of contemporary LLMs by conducting experiments with varying architectures.
Anthology ID:
2025.findings-acl.832
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
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
16180–16193
Language:
URL:
https://preview.aclanthology.org/mtsummit-25-ingestion/2025.findings-acl.832/
DOI:
10.18653/v1/2025.findings-acl.832
Bibkey:
Cite (ACL):
Seungyoon Lee, Seongtae Hong, Hyeonseok Moon, and Heuiseok Lim. 2025. Semantic Aware Linear Transfer by Recycling Pre-trained Language Models for Cross-lingual Transfer. In Findings of the Association for Computational Linguistics: ACL 2025, pages 16180–16193, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
Semantic Aware Linear Transfer by Recycling Pre-trained Language Models for Cross-lingual Transfer (Lee et al., Findings 2025)
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PDF:
https://preview.aclanthology.org/mtsummit-25-ingestion/2025.findings-acl.832.pdf