A Multilingual Red Teaming–Driven Safety Analysis of LLMs
Summary
The paper examines how well large language models resist harmful requests in more than one language, with a focus on English and Portuguese. The authors built a bilingual test set of 170 prompts per language. It combines handpicked items from two public red teaming collections with a smaller in-house set that imitates ordinary users probing the model, for example through euphemisms. Prompts were machine-translated into Portuguese with GPT-4o and then checked by a native speaker. A single annotator labelled every response. Results are reported as a binary safety percentage and as a finer-grained safety score built from +1/−1 categories. Three experiments were run: a five-model comparison, tests with guardrailing and content-moderation system prompts, and a study of how token limits and temperature affect TowerLLM 3.0 models. TowerLLM variants outperformed GPT-4o on safety. Portuguese results were consistently weaker than English, and LLM-based content moderation performed poorly. The work argues for multilingual safety testing and suggests red teaming as a new professional role for translators.
Key points
- Data: 72 requests come from Haize Labs' Redteaming Resistance Leaderboard dataset, 50 from Babelscape's ALERT, and 48 were newly written, giving 340 requests in total across EN and PT. Twenty of them are two-part prompts. The set is released as
Unbabel/Multilingual-Red-Teamingon Hugging Face. - Model comparison: Five models were tested: GPT-4o, Vesuvius 3.0, Sugarloaf 3.1, Sugarloaf 4.0 and Vesuvius 4.0. Sugarloaf 3.1 was safest overall, while Vesuvius 4.0 led on the Portuguese safety score. Both beat GPT-4o.
- Guardrailing prompt: Mistral AI's Safe Prompt improved safety, with the clearest gains in Portuguese.
- Content moderation: Mistral's Self-reflection Prompt and a Llama Guard 3-8B prompt both gave substandard harm classification. GPT-4o did best on this task, and Vesuvius 3.0 surprisingly outperformed the newer Sugarloaf 3.1.
- Decoding settings: TowerLLM 3.0 models (Anthill, Sugarloaf, Vesuvius) were tested at 512/1000/2048 tokens with temperature 0 or 1. The 1000-token, temperature-1 setting was safest, while 512 tokens was markedly poor. Higher temperature reduced harmful content but caused more failed requests.
Cite
@inproceedings{pandeiro2026multilingual,
title = {{A Multilingual Red Teaming–Driven Safety Analysis of LLMs}},
author = {Pandeiro, Patrícia and Cabarrão, Vera and Moniz, Helena},
booktitle = {Proceedings of the 26th Annual Conference of the European Association for Machine Translation (Volume 1)},
year = {2026},
url = {https://aclanthology.org/2026.eamt-1.46/}
}References
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