Language Models’ Factuality Depends on the Language of Inquiry

ACL ARR 2025 February Submission5150 Authors

Abstract: Multilingual language models (LMs) are expected to recall factual knowledge consistently across languages, yet they often fail to transfer knowledge between languages even when they possess the correct information in one of the languages. For example, we find that an LM may correctly identify Rashed Al Shashai as being from Saudi Arabia when asked in Arabic, but consistently fails to do so when asked in English or Swahili. To systematically investigate this limitation, we introduce a benchmark of 10,000 country-related facts across 13 languages and propose three novel metrics—Factual Recall Score, Knowledge Transferability Score, and Cross-Lingual Factual Knowledge Transferability Score—to quantify factual recall and knowledge transferability in LMs across different languages. Our results reveal fundamental weaknesses in today's state-of-the-art LMs, particularly in cross-lingual generalization where models fail to transfer knowledge effectively across different languages, leading to inconsistent performance sensitive to the language used. Our findings emphasize the need for LMs to recognize language-specific factual reliability and leverage the most trustworthy information across languages. We release our benchmark and evaluation framework to drive future research in multilingual knowledge transfer.

Paper Type: Long

Research Area: Multilingualism and Cross-Lingual NLP

Research Area Keywords: mixed language, multilingualism, linguistic variation, cross-lingual transfer, multilingual benchmarks, multilingual evaluation, dialects and language varieties, less-resourced languages, minoritized languages, resources for less-resourced languages

Contribution Types: Model analysis & interpretability, Approaches to low-resource settings, Data resources, Data analysis

Languages Studied: English, French, Chinese, Japanese, Hindi, Russian, Arabic, Greek, Turkish, Swahili, Nepali, Ukrainian, Thai

Submission Number: 5150