Examining Multilingual Embedding Models Cross-Lingually Through LLM-Generated Adversarial Examples

Andrianos Michail, Simon Clematide, Rico Sennrich


Abstract
The evaluation of cross-lingual semantic search models is often limited to existing datasets from tasks such as information retrieval and semantic textual similarity. We introduce Cross-Lingual Semantic Discrimination (CLSD), a lightweight evaluation task that requires only parallel sentences and a Large Language Model (LLM) to generate adversarial distractors. CLSD measures an embedding model’s ability to rank the true parallel sentence above semantically misleading but lexically similar alternatives. As a case study, we construct CLSD datasets for German–French in the news domain. Our experiments show that models fine-tuned for retrieval tasks benefit from pivoting through English, whereas bitext mining models perform best in direct cross-lingual settings. A fine-grained similarity analysis further reveals that embedding models differ in their sensitivity to linguistic perturbations.
Anthology ID:
2025.findings-emnlp.115
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2025
Month:
November
Year:
2025
Address:
Suzhou, China
Editors:
Christos Christodoulopoulos, Tanmoy Chakraborty, Carolyn Rose, Violet Peng
Venue:
Findings
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Publisher:
Association for Computational Linguistics
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Pages:
2161–2170
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URL:
https://aclanthology.org/2025.findings-emnlp.115/
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Cite (ACL):
Andrianos Michail, Simon Clematide, and Rico Sennrich. 2025. Examining Multilingual Embedding Models Cross-Lingually Through LLM-Generated Adversarial Examples. In Findings of the Association for Computational Linguistics: EMNLP 2025, pages 2161–2170, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
Examining Multilingual Embedding Models Cross-Lingually Through LLM-Generated Adversarial Examples (Michail et al., Findings 2025)
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https://aclanthology.org/2025.findings-emnlp.115.pdf
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