Paths Not Taken: Understanding and Mending the Multilingual Factual Recall Pipeline

Meng Lu, Ruochen Zhang, Carsten Eickhoff, Ellie Pavlick


Abstract
Multilingual large language models (LLMs) often exhibit factual inconsistencies across languages, usually with better performance in factual recall tasks in high-resource languages than in other languages. The causes of these failures, however, remain poorly understood. Using mechanistic analysis techniques, we uncover the underlying pipeline that LLMs employ, which involves using the English-centric factual recall mechanism to process multilingual queries and then translating English answers back into the target language. We identify two primary sources of error: insufficient engagement of the reliable English-centric mechanism for factual recall, and incorrect translation from English back into the target language for the final answer. To address these vulnerabilities, we introduce two vector interventions, both independent of languages and datasets, to redirect the model toward better internal paths for higher factual consistency. Our interventions combined increase the recall accuracy by over 35 percent for the lowest-performing language. Our findings demonstrate how mechanistic insights can be used to unlock latent multilingual capabilities in LLMs.
Anthology ID:
2025.emnlp-main.762
Volume:
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Month:
November
Year:
2025
Address:
Suzhou, China
Editors:
Christos Christodoulopoulos, Tanmoy Chakraborty, Carolyn Rose, Violet Peng
Venue:
EMNLP
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Publisher:
Association for Computational Linguistics
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Pages:
15077–15107
Language:
URL:
https://preview.aclanthology.org/ingest-emnlp/2025.emnlp-main.762/
DOI:
Bibkey:
Cite (ACL):
Meng Lu, Ruochen Zhang, Carsten Eickhoff, and Ellie Pavlick. 2025. Paths Not Taken: Understanding and Mending the Multilingual Factual Recall Pipeline. In Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing, pages 15077–15107, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
Paths Not Taken: Understanding and Mending the Multilingual Factual Recall Pipeline (Lu et al., EMNLP 2025)
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