Abstract
Cross-lingual voice cloning aims to generate speech in a target language while preserving speaker identity from a source-language reference. This task is central to speech translation and is the focus of the IWSLT 2026 Cross-Lingual Voice Cloning track. A key challenge is maintaining intelligibility and naturalness in the presence of accent variation and domain-specific vocabulary. We build on a multilingual text-to-speech model, FishAudio-S2-Pro, and introduce language tag prompting to improve language control and reduce accent leakage. We further apply reinforcement learning (RL) fine-tuning for task adaptation and observe improvements in intelligibility. Finally, we propose a reference-conditioned lexical matching method that improves pronunciation of domain-specific terms when lexical overlap is present. Results show that language prompting provides the largest gains, while lexical matching yields consistent improvements on matched subsets.- Anthology ID:
- 2026.iwslt-1.8
- Volume:
[Proceedings of the 23rd International Conference on Spoken Language Translation (IWSLT 2026)](/volumes/2026.iwslt-1/)- Month:
- July
- Year:
- 2026
- Address:
- San Diego, USA (in-person and online)
- Editors:
Elizabeth Salesky,Antonios Anastasopoulos,Matteo Negri,Marcello Federico- Venues:
[IWSLT](/venues/iwslt/)|[WS](/venues/ws/)- SIG:
[SIGSLT](/sigs/sigslt/)- Publisher:
- Association for Computational Linguistics
- Note:
- Pages:
- 78–83
- Language:
- URL:
[https://aclanthology.org/2026.iwslt-1.8/](https://aclanthology.org/2026.iwslt-1.8/)- DOI:
- Cite (ACL):
- Seymanur Akti and Alexander Waibel. 2026. KIT’s Submission to Cross-Lingual Voice Cloning in IWSLT 2026. InProceedings of the 23rd International Conference on Spoken Language Translation (IWSLT 2026), pages 78–83, San Diego, USA (in-person and online). Association for Computational Linguistics. - Cite (Informal):
[KIT’s Submission to Cross-Lingual Voice Cloning in IWSLT 2026](https://aclanthology.org/2026.iwslt-1.8/)(Akti & Waibel, IWSLT 2026)- PDF:
[https://aclanthology.org/2026.iwslt-1.8.pdf](https://aclanthology.org/2026.iwslt-1.8.pdf)