Khai-Nguyen Nguyen
Author directory2026
Deep and shallow biases in language models
An Vo | Vy Tuong Dang | Khai-Nguyen Nguyen | Emilio Villa-Cueva | Thamar Solorio | Anh Totti Nguyen | Daeyoung Kim
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
An Vo | Vy Tuong Dang | Khai-Nguyen Nguyen | Emilio Villa-Cueva | Thamar Solorio | Anh Totti Nguyen | Daeyoung Kim
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Large language models often repeatedly select the same answer even when many alternatives are plausible. Prior work treats this concentration as bias, but it does not distinguish stable model preferences from responses that depend on a particular prompt wording. We introduce a bias depth score that measures both how strongly a model prefers its top answer under direct prompting and whether that answer survives scenario reframing. Across 4,442 opinion prompts and four large language models, only about a quarter of the concentrated preferences survive reframing. We call these persistent cases Deep biases, and the remaining prompt-dependent cases Shallow biases. Our results show that Deep biases are more often inherited from pretraining and preserved through SFT. Under both continued fine-tuning and prompt-based debiasing for diversity, Deep biases are consistently harder to remove than Shallow biases. Bias depth therefore separates stable learned biases from prompt-wording artifacts that single-prompt metrics conflate. Code, models, and data are available at https://deepbias.github.io.
2025
Medical Spoken Named Entity Recognition
Khai Le-Duc | David Thulke | Hung-Phong Tran | Long Vo-Dang | Khai-Nguyen Nguyen | Truong-Son Hy | Ralf Schlüter
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 3: Industry Track)
Khai Le-Duc | David Thulke | Hung-Phong Tran | Long Vo-Dang | Khai-Nguyen Nguyen | Truong-Son Hy | Ralf Schlüter
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 3: Industry Track)
Spoken Named Entity Recognition (NER) aims to extract named entities from speech and categorise them into types like person, location, organization, etc. In this work, we present VietMed-NER - the first spoken NER dataset in the medical domain. To our knowledge, our Vietnamese real-world dataset is the largest spoken NER dataset in the world regarding the number of entity types, featuring 18 distinct types. Furthermore, we present baseline results using various state-of-the-art pre-trained models: encoder-only and sequence-to-sequence; and conduct quantitative and qualitative error analysis. We found that pre-trained multilingual models generally outperform monolingual models on reference text and ASR output and encoders outperform sequence-to-sequence models in NER tasks. By translating the transcripts, the dataset can also be utilised for text NER in the medical domain in other languages than Vietnamese. All code, data and models are publicly available.
Sentiment Reasoning for Healthcare
Khai-Nguyen Nguyen | Khai Le-Duc | Bach Phan Tat | Le Duy | Long Vo-Dang | Truong-Son Hy
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 6: Industry Track)
Khai-Nguyen Nguyen | Khai Le-Duc | Bach Phan Tat | Le Duy | Long Vo-Dang | Truong-Son Hy
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 6: Industry Track)
Transparency in AI healthcare decision-makingis crucial. By incorporating rationales to explain reason for each predicted label, userscould understand Large Language Models(LLMs)’s reasoning to make better decision.In this work, we introduce a new task - Sentiment Reasoning - for both speech and textmodalities, and our proposed multimodal multitask framework and the world’s largest multimodal sentiment analysis dataset. Sentiment Reasoning is an auxiliary task in sentiment analysis where the model predicts boththe sentiment label and generates the rationale behind it based on the input transcript.Our study conducted on both human transcriptsand Automatic Speech Recognition (ASR) transcripts shows that Sentiment Reasoning helpsimprove model transparency by providing rationale for model prediction with quality semantically comparable to humans while alsoimproving model’s classification performance(+2% increase in both accuracy and macro-F1) via rationale-augmented fine-tuning. Also,no significant difference in the semantic quality of generated rationales between human andASR transcripts. All code, data (five languages - Vietnamese, English, Chinese, German, andFrench) and models are published online.