I am currently a postdoctoral research fellow with Speech Lab, College of Computing and Data Science, at Nanyang Technological University, supervised by Prof. Eng Siong Chng.
Prior to joining NTU Speech Lab, I received my Ph.D. from School of Electronic and Electrical Engineering at Nanyang Technological University, under the supervision of Prof. Andy W. H. Khong (EEE, Nanyang Technological University) and Dr. Leibny Paola Garcia (CLSP, The Johns Hopkins Univerisity). Apart from my supervisors, I also work closely with Prof. Suzy J. Styles (NTU), Prof. Sanjeev Khudanpur (JHU), and Prof. Shinji Watanabe (CMU).

My research topics are:

• Spoken Language Recognition: Language identification and diarization

• Speech Recognition: Code-switching and multilingual speech recognition

• Large-scale Pre-trained Model: Adaptation and application methods for large-scale pre-trained models

📖 Educations

• 2018.08 - 2023.05, Ph.D., Nanyang Technological University.
  Thesis: Enhancing Spoken Language Identification and Diarization for Multilingual Speech
  Supervisors: Prof. Andy W. H. Khong (NTU) & Dr. Leibny Paola Garcia (JHU)
• 2017.08 - 2018.05, Ms.C., Nanyang Technological University.
• 2012.09 - 2016.07, B.Eng, Harbin Institute of Technology.
  Supervisor: Prof. Chenguang He

📝 Publications

• IEEE JSTSP SAV-SE: Scene-aware Audio-Visual Speech Enhancement with Selective State Space Model, Xinyuan Qian, Jiaran Gao, Yaodan Zhang, Qiquan Zhang, Hexin Liu, Leibny Paola Garcia, Haizhou Li.

• ICLR 2025 GenSE: Generative Speech Enhancement via Language Models using Hierarchical Modeling, Jixun Yao, Hexin Liu, Chen Chen, Yuchen Hu, Eng Siong Chng, Lei Xie.

• IEEE TCE Selective State Space Model for Monaural Speech Enhancement, Moran Chen, Qiquan Zhang, Mingjiang Wang, Xiangyu Zhang, Hexin Liu, Eliathamby Ambikairaiah, Deying Chen.

• ICASSP 2025 Adapting Whisper for Code-Switching through Encoding Refining and Language-Aware Decoding, Jiahui Zhao, Hao Shi, Chenrui Cui, Tianrui Wang, Hexin Liu, Zhaoheng Ni, Lingxuan Ye, Longbiao Wang.

• Interspeech 2024 Bridging Child-Centered Speech Language Identification and Language Diarization via Phonetics, Yujia Wang, Hexin Liu, Leibny Paola Garcia.

• IEEE TASLP Mamba in Speech: Towards an Alternative to Self-Attention, Xiangyu Zhang*, Qiquan Zhang*, Hexin Liu*, Tianyi Xiao, Xinyuan Qian, Beena Ahmed, Eliathamby Ambikairajah, Haizhou Li, Julien Epps.

• Preprint Aligning Speech to Languages to Enhance Code-switching Speech Recognition, Hexin Liu, Xiangyu Zhang, Leibny Paola Garcia, Andy W.H. Khong, Eng Siong Chng, Shinji Watanabe.

• EMNLP 2024 When LLMs Meets Acoustic Landmarks: An Efficient Approach to Integrate Speech into Large Language Models for Depression Detection, Xiangyu Zhang, Hexin Liu, Kaishuai Xu, Qiquan Zhang, Daijiao Liu, Beena Ahmed, Julien Epps.

• EMNLP 2024 Speaking in Wavelet Domain: A Simple and Efficient Approach to Speed up Speech Diffusion Model, Xiangyu Zhang, Daijiao Liu, Hexin Liu, Qiquan Zhang, Hanyu Meng, Leibny Paola Garcia, Eng Siong Chng, Lina Yao.

• ICNSLP 2023 A Quantitative Approach to Understand Self-Supervised Models as Cross-lingual Feature Extractors, Shuyue Stella Li, Beining Xu, Xiangyu Zhang, Hexin Liu, Wenhan Chao, Leibny Paola Garcia.

• Preprint Generative error correction for code-switching speech recognition using large language models, Chen Chen, Yuchen Hu, Chao-Han Huck Yang, Hexin Liu, Sabato Marco Siniscalchi, Eng Siong Chng.

• ICASSP 2024 Enhancing Code-switching Speech Recognition with Interactive Language Biases, Hexin Liu, Leibny Paola Garcia, Xiangyu Zhang, Andy W.H. Khong, Sanjeev Khudanpur.

• ICASSP 2024 Unidirectional brain-computer interface: Artificial neural network encoding natural images to fMRI response in the visual cortex, Ruixing Liang, Xiangyu Zhang, Qiong Li, Lai Wei, Hexin Liu, Avisha Kumar, Kelley M Kempski Leadingham, Joshua Punnoose, Leibny Paola Garcia, Amir Manbachi.

• ICASSP 2023 PQLM - Multilingual Decentralized Portable Quantum Language Model, Shuyue Stella Li, Xiangyu Zhang, Shu Zhou, Hongchao Shu, Ruixing Liang, Hexin Liu, Leibny Paola Garcia.

• ICASSP 2023 Reducing Language Confusion for Code-switching Speech Recognition with Token-level Language Diarization, Hexin Liu, Haihua Xu, Leibny Paola Garcia, Andy W.H. Khong, Yi He, Sanjeev Khudanpur.

• Interspeech 2023(Oral) Investigating Model Performance in Language Identification: Beyond Simple Error Statistics, Suzy J. Styles, Victoria Y.H. Chua, Fei Ting Woon, Hexin Liu, Leibny Paola Garcia, Sanjeev Khudanpur, Andy W.H. Khong, Justin Dauwels.

• Interspeech 2023 MERLIon CCS Challenge: A English-Mandarin code-switching child-directed speech corpus for language identification and diarization, Victoria YH Chua*, Hexin Liu*, Leibny Paola Garcia, Fei Ting Woon, Jinyi Wong, Xiangyu Zhang, Sanjeev Khudanpur, Andy W.H. Khong, Justin Dauwels, Suzy J Styles.

• Interspeech 2023 Self-supervised Learning Representation based Accent Recognition with Persistent Accent Memory, Rui Li, Zhiwei Xie, Haihua Xu, Yizhou Peng, Hexin Liu, Hao Huang, Eng Siong Chng.

• IEEE JSTSP Efficient self-supervised learning representations for spoken language identification, Hexin Liu, Leibny Paola Garcia, Andy W.H. Khong, Eng Siong Chng, Suzy J. Styles, Sanjeev Khudanpur.

• Odyssey 2022 Enhancing Language Identification using Dual-mode Model with Knowledge Distillation, Hexin Liu, Leibny Paola Garcia, Andy W.H. Khong, Justin Dauwels, Suzy J. Styles, Sanjeev Khudanpur.

• Interspeech 2022(Oral) PHO-LID: A Unified Model Incorporating Acoustic-Phonetic and Phonotactic Information for Language Identification, Hexin Liu, Leibny Paola Garcia, Andy W.H. Khong, Suzy J. Styles, Sanjeev Khudanpur.

• Interspeech 2021 End-to-end language diarization for bilingual code-switching speech, Hexin Liu, Leibny Paola Garcia, Xinyi Zhang, Justin Dauwels, Andy W.H. Khong, Sanjeev Khudanpur, Suzy J. Styles.

🧑‍🔬 Services

• Reviewer:  ICASSP(23-24), Interspeech(2022-24), ASRU(2022-24), SLT(2022-24), COLING(2024-25), IEEE TASLP, SPL, ESWA
• Session Chair:  Interspeech (2023), APSIPA-TPC (2025-27), IALP (2024), IPC of ASR Summer School (2025)
• Others:  Mentor in IEEE SLT 2022 Hackthon

💻 Work Experiences

• 2022.08 - 2023.01, Research Scientist Intern, Bytedance AI Lab, Singapore.
• 2023.04 - 2023.08, Research Associate, Delta-NTU Corp Lab, Nanyang Technological University.
• 2023.09 - now, Research Fellow, Speech Lab, Nanyang Technological University.

💬 Invited talks

• 2024.06，IEEE & APSIPA SG chapters joint Seminar: Emerging Trends and Innovations in Machine Learning and AI
  Automatic speech recognition with large language models [slides]