@inproceedings{xie-etal-2025-language,
    title = "Can Language Neuron Intervention Reduce Non-Target Language Output?",
    author = "Xie, Suchun  and
      Kim, Hwichan  and
      Sasaki, Shota  and
      Yamada, Kosuke  and
      Suzuki, Jun",
    editor = "Belinkov, Yonatan  and
      Mueller, Aaron  and
      Kim, Najoung  and
      Mohebbi, Hosein  and
      Chen, Hanjie  and
      Arad, Dana  and
      Sarti, Gabriele",
    booktitle = "Proceedings of the 8th BlackboxNLP Workshop: Analyzing and Interpreting Neural Networks for NLP",
    month = nov,
    year = "2025",
    address = "Suzhou, China",
    publisher = "Association for Computational Linguistics",
    url = "https://preview.aclanthology.org/author-page-diogo-silva-nova/2025.blackboxnlp-1.26/",
    doi = "10.18653/v1/2025.blackboxnlp-1.26",
    pages = "452--466",
    ISBN = "979-8-89176-346-3",
    abstract = "Large language models (LLMs) often fail to generate text in the intended target language, particularly in non-English interactions. Concurrently, recent work has explored Language Neuron Intervention (LNI) as a promising technique for steering output language. In this paper, we re-evaluate LNI in more practical scenarios{---}specifically with instruction-tuned models and prompts that explicitly specify the target language. Our experiments show that while LNI also shows potential in such practical scenarios, its average effect is limited and unstable across models and tasks, with a 0.83{\%} reduction in undesired language output and a 0.1{\%} improvement in performance. Our further analysis identifies two key factors for LNI{'}s limitation: (1) LNI affects both the output language and the content semantics, making it hard to control one without affecting the other, which explains the weak performance gains. (2) LNI increases the target language token probabilities, but they often remain below the top-1generation threshold, resulting in failure to generate the target language in most cases. Our results highlight both the potential and limitations of LNI, paving the way for future improvements."
}