Ready to Translate, Not to Represent? Bias and Performance Gaps in Multilingual LLMs Across Language Families and Domains
Paper · 2026 · Md. Faiyaz Abdullah Sayeedi, Subhey Sadi Rahman, Md. Mahbub Alam et al.
Summary
The paper asks whether open-source LLMs that translate fluently also translate fairly across language families, translation directions and specialised domains. The authors present TranslationTangles, a combined framework and dataset. It benchmarks 24 bidirectional language pairs drawn from public parallel corpora, grouped by linguistic sub-family and by domain, and compares small, medium and large models. Several automatic metrics are reported, including BLEU, chrF, BERTScore and COMET. For bias, they built a hybrid detector with three parts: spaCy NER and curated keyword lexicons spot inserted or erased sensitive terms, gemini-embedding-001 cosine similarity filters these candidates, and an LLM-as-a-Judge step validates the result. Human annotators labelled 1,439 translation-reference pairs, which serve as a gold standard. The main finding is that strong metric scores can hide cultural, religious or social distortions. The heuristic detector catches every human-marked case but over-flags heavily, while the LLM judge is more balanced. This matters because standard MT metrics alone can certify translations that misrepresent content, especially for low-resource source languages.
Key points
- The resource contains reference translations, LLM outputs, bias labels from several detectors, and human annotations over six categories: gender, religious, cultural, sociocultural, social and racial. It is hosted at github.com/faiyazabdullah/TranslationTangles.
- A translation is flagged only when NER or keyword checks detect a change and the similarity falls below τ = 0.75. This threshold was chosen at the "knee" of the bias-count curve.
- Measured against human labels, the heuristic-semantic system has zero false negatives but 832 false positives, giving about 27.3% precision and 42.1% accuracy. LLM-as-a-Judge reaches 35.1% precision, 95.5% recall and 60.4% accuracy, with 299 TP, 552 FP, 14 FN and 574 TN.
- Several outputs were accurate but still biased:
- gemma-2-9b produced 290 biased translations despite good metric scores.
- The gu-en pair showed 183 cultural-bias cases.
- Llama-3.1-70b rendered the Russian word for "church" as "temple".
- The authors list these limitations:
- Bias detection covers only the X→EN direction.
- Subtle harms such as sarcasm or omission are missed.
- Only open-source models were tested.
Institutions
Fields, topics and concepts
📚 Shelves 4The field of science this work belongs to (OpenAlex fields).Computer Science · 16,667 worksArtificial Intelligence · 16,194 worksArts and Humanities · 16,039 worksLanguage and Linguistics · 15,891 works
🧭 Topics 2Research subjects and languages the work is about.Language models & pretraining · 3,320 worksMultilingual & cross-lingual NLP · 828 works
Cite
Cite as Md. Faiyaz Abdullah Sayeedi, Subhey Sadi Rahman, Md. Mahbub Alam, Md. Adnanul Islam, Jannatul Ferdous Deepti, Tasnim Mohiuddin, Md Mofijul Islam and Swakkhar Shatabda. 2026. Ready to Translate, Not to Represent? Bias and Performance Gaps in Multilingual LLMs Across Language Families and Domains. Findings of the Association for Computational Linguistics: ACL 2026.
@inproceedings{sayeedi2026ready,
title = {{Ready to Translate, Not to Represent? Bias and Performance Gaps in Multilingual LLMs Across Language Families and Domains}},
author = {Md. Faiyaz Abdullah Sayeedi, Subhey Sadi Rahman, Md. Mahbub Alam, Md. Adnanul Islam, Jannatul Ferdous Deepti, Tasnim Mohiuddin, Md Mofijul Islam and Swakkhar Shatabda},
booktitle = {Findings of the Association for Computational Linguistics: ACL 2026},
year = {2026},
doi = {10.18653/v1/2026.findings-acl.68},
url = {https://doi.org/10.18653/v1/2026.findings-acl.68}
}References
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