Lester Phillip Violeta
Research Scientist (Speech LLMs & Post-Training)
DubGuild, Tokyo, Japan
I am a Research Scientist at DubGuild in Tokyo, where I work on scaling and post-training speech LLMs for natural conversation. My research interests sit at the intersection of speech generation and LLM post-training: reinforcement learning for spoken dialogue behavior, neural audio representations, and large-scale evaluation methodology.
I received my Ph.D. in Computer Science from Nagoya University at Toda Laboratory under the supervision of Professor Tomoki Toda, where my research on speech synthesis, voice conversion, and speech recognition was published in top speech and audio venues such as Interspeech, ICASSP, ASRU, SLT, and IEEE/ACM TASLP. I was the main organizer of the Singing Voice Conversion Challenge in 2023 and 2025, and I serve on the peer-review committees of conferences such as ASRU, SLT, ICASSP, Interspeech, and IJCNN, and journals like IEEE JSTSP.
I have a deep international background now based in Japan, having done my B.S. in the Philippines and a research exchange in France. Outside of research, I like bouldering (check out this page) and learning Japanese.
News
🎓 Graduated with my Ph.D. from Nagoya University!
Education
Nagoya University, Japan
Ph.D. Computer Science
Advisor: Prof. Tomoki Toda
Thesis: Speech Synthesis, Voice Conversion
Nagoya University, Japan
M.S. Computer Science
Advisor: Prof. Tomoki Toda
Thesis: Speech Recognition
Ateneo de Manila University, Philippines
B.S. Electronics Engineering
Thesis: Renewable Energy, Microgrid Optimization
Institut Catholique d'Arts et Metiers Paris, France
Research Exchange Semester
Thesis: Renewable Energy, Microgrid Optimization
Publications
Technical Report 2026
Scaling Japanese Speech Foundation Models and Examining TTS Performance (in Japanese)
長谷川 直哉, 相田 優希, 廣岡 聖司, 林 春太朗, Lester Phillip Violeta, 大嶽 匡俊
ICASSP 2026
The Singing Voice Conversion Challenge 2025: From Singer Identity Conversion To Singing Style Conversion
Lester Phillip Violeta, Xueyao Zhang, Jiatong Shi, Yusuke Yasuda, Wen-Chin Huang, Zhizheng Wu, Tomoki Toda
ICASSP 2024
Electrolaryngeal Speech Intelligibility Enhancement through Robust Linguistic Encoders
Lester Phillip Violeta, Wen-Chin Huang, Ding Ma, Ryuichi Yamamoto, Kazuhiro Kobayashi, Tomoki Toda
IEEE/ACM TASLP 2024
Pretraining and Adaptation Techniques for Electrolaryngeal Speech Recognition
Lester Phillip Violeta, Ding Ma, Wen-Chin Huang, Tomoki Toda
Technical Report 2024
A Preliminary Investigation on Flexible Singing Voice Synthesis Through Decomposed Framework with Inferrable Features
Lester Phillip Violeta, Taketo Akama
ASRU 2023
The Singing Voice Conversion Challenge 2023
Wen-Chin Huang, Lester Phillip Violeta, Songxiang Liu, Jiatong Shi, Tomoki Toda
APSIPA 2023
An Analysis of Personalized Speech Recognition System Development for the Deaf and Hard-of-hearing
Lester Phillip Violeta, Tomoki Toda
ICASSP 2023
Intermediate Fine-tuning Using Imperfect Synthetic Speech for Improving Electrolaryngeal Speech Recognition
Lester Phillip Violeta, Ding Ma, Wen-Chin Huang, Tomoki Toda
Interspeech 2022
Investigating Self-Supervised Pretraining Frameworks for Pathological Speech Recognition
Lester Phillip Violeta, Wen-Chin Huang, Tomoki Toda