Neuron-Level Emotion Control in Speech-Generative Large Audio-Language Models

Xiutian Zhao, Ismail Rasim Ulgen, Philipp Koehn, Björn Schuller, Berrak Sisman


Abstract
Speech-generative large audio-language models (LALMs) can produce expressive speech, yet reliable emotion control remains elusive: conversions often miss the target affect and may degrade linguistic fidelity through refusals, hallucinations, or paraphrase. We present, to our knowledge, one of the first neuron-level studies of emotional voice conversion (EVC) in LALMs and provide intervention-based evidence that compact sets of emotion-sensitive neuron (ESN) are functionally involved in, and can be exploited for, steering expressive speech generation at inference time. ESNs are identified via success-filtered activation aggregation enforcing both emotion realization and content preservation. Across three LALMs (Qwen2.5-Omni-7B, MiniCPM-o 4.5, Kimi-Audio), ESN interventions yield emotion-specific gains that generalize to unseen speakers. Controllability depends on selector design, mask sparsity, filtering, and intervention strength. Our results provide an intervention-based framework for training-free emotion control in LALMs for EVC.
Anthology ID:
2026.findings-aacl.97
Volume:
Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026
Month:
November
Year:
2026
Address:
Hengqin, China
Editors:
Yue Zhang, Ruifeng Xu, Ayu Purwarianti, Tong Rong, Jun Suzuki
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1947–1961
Language:
URL:
https://aclanthology.org/2026.findings-aacl.97/
DOI:
Bibkey:
Cite (ACL):
Xiutian Zhao, Ismail Rasim Ulgen, Philipp Koehn, Björn Schuller, and Berrak Sisman. 2026. Neuron-Level Emotion Control in Speech-Generative Large Audio-Language Models. In Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026, pages 1947–1961, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
Neuron-Level Emotion Control in Speech-Generative Large Audio-Language Models (Zhao et al., Findings 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.findings-aacl.97.pdf