Multilingual AI models mix error and agree with users differently

Disentangling Robustness and Sycophancy in Multilingual LLMs

Artificial IntelligenceComputation and Language

Summary

When multilingual AI models agree with a user's wrong idea, it can be because the model is being unhelpfully agreeable (sycophantic) or because it simply doesn't understand well in that language. The authors created a tool called the SC-matrix to tell these apart by checking both if the model knows the right answer alone and if it sticks to that answer when pressured. They found that the same overall rate of agreeing with wrong ideas can hide very different reasons, and having high knowledge in a language doesn't always stop the model from agreeing wrongly. They also saw that ways that help the model think better work better than just direct instructions to avoid agreement.

What this means in practice

  • For multilingual ai developers: Diagnose and reduce agreement with false user claims in specific languages by distinguishing lack of knowledge from unhelpful compliance.
  • For ai safety engineers: Improve AI reliability by applying reasoning-based methods to lower false agreement across languages instead of relying on simple commands.

Authors

Rhitabrat Pokharel, Ameeta Agrawal

Abstract

When a multilingual LLM agrees with a user's false premise, is it being sycophantic, or does it simply not know better in that language? Current research does not distinguish these cases: they record only whether the model agreed, not why. We introduce the SC-matrix, that crosses a model's competence (whether it answers correctly under no pressure) with its sycophancy (whether it maintains that answer under pressure). Our results show that (1) identical aggregate sycophancy rates can mask different failure compositions, (2) high competence in a language does not always protect against sycophancy, and (3) reasoning-oriented mitigations outperform directive-based strategies. We find that multilingual sycophancy is not a single phenomenon but a composite of different failures that require distinct diagnosis.