Can Dialects Be Steered Like Languages? Sparse Neurons and Distributed Directions in Arabic LLMs

Kareem Elozeiri, Mervat Abassy, Omar Kallas, Fahim Dalvi, Preslav Nakov, Kentaro Inui, Nadir Durrani


Abstract
A key challenge in Arabic NLP is the scarcity of dialectal data relative to Modern Standard Arabic (MSA), causing LLMs to overproduce MSA and struggle with dialectally accurate generation. From an interpretability perspective, this raises a fundamental question: where and how are dialectal features encoded within model internals, and can these representations be leveraged to improve dialect generation without fine-tuning? This study investigates two complementary inference-time approaches that serve simultaneously as interpretability probes and control mechanisms. First, we conduct a neuron-level analysis, identifying sparse neuron populations that encode dialect-specific features and showing that amplifying or suppressing these neurons can steer model outputs toward target dialects. Second, motivated by the entanglement of dialectal features at the single-neuron level, we apply a vector-steering approach that extracts dialect-specific activation directions and injects them during inference. Together, these methods illuminate the geometry of dialectal knowledge in Arabic LLMs and offer a principled, interpretability-grounded framework for dialect control without requiring dialect-specific fine-tuning.
Anthology ID:
2026.findings-emnlp.2369
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
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SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
50894–50918
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URL:
https://aclanthology.org/2026.findings-emnlp.2369/
DOI:
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Cite (ACL):
Kareem Elozeiri, Mervat Abassy, Omar Kallas, Fahim Dalvi, Preslav Nakov, Kentaro Inui, and Nadir Durrani. 2026. Can Dialects Be Steered Like Languages? Sparse Neurons and Distributed Directions in Arabic LLMs. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 50894–50918, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Can Dialects Be Steered Like Languages? Sparse Neurons and Distributed Directions in Arabic LLMs (Elozeiri et al., Findings 2026)
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https://aclanthology.org/2026.findings-emnlp.2369.pdf