Cross-Lingual Semantic Fusion: Towards Universal Sentence Representations via LLMs

Zhen Hu, Zhu Liu, Ying Liu


Abstract
Extracting sentence representations from pretrained large language models (LLMs) is a training-free approach that leverages their inherent semantic understanding. Existing methods primarily rely on prompt engineering to distill core semantics, but the resulting representations often retain language-specific features that hinder semantic tasks. Moreover, these approaches fail to exploit the cross-lingual capabilities of LLMs, remaining confined to monolingual settings. To address these limitations, we propose CLSF, a novel method that actively introduces diverse language perturbations when encoding the same sentence and then fuses the perturbed embeddings, effectively reducing language-specific biases and producing a more universal representation. CLSF is plug-and-play and can be integrated with existing prompt-based methods. Experiments on Semantic Textual Similarity (STS), multilingual alignment, and various downstream tasks show that CLSF consistently improves performance across different LLMs.
Anthology ID:
2026.aacl-long.196
Volume:
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
November
Year:
2026
Address:
Hengqin, China
Editors:
Yue Zhang, Ruifeng Xu, Ayu Purwarianti, Tong Rong, Jun Suzuki
Venues:
AACL | IJCNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
4359–4374
Language:
URL:
https://aclanthology.org/2026.aacl-long.196/
DOI:
Bibkey:
Cite (ACL):
Zhen Hu, Zhu Liu, and Ying Liu. 2026. Cross-Lingual Semantic Fusion: Towards Universal Sentence Representations via LLMs. In Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers), pages 4359–4374, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
Cross-Lingual Semantic Fusion: Towards Universal Sentence Representations via LLMs (Hu et al., AACL-IJCNLP 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.aacl-long.196.pdf