Viet Thanh Pham
Author directory2026
Distributional Alignment for Large Language Models under Domain Shift
Viet Thanh Pham | Lizhen Qu | Zhuang Li | Gholamreza Haffari
Findings of the Association for Computational Linguistics: ACL 2026
Viet Thanh Pham | Lizhen Qu | Zhuang Li | Gholamreza Haffari
Findings of the Association for Computational Linguistics: ACL 2026
Distributional alignment enables large language models (LLMs) to predict how a target population distributes its responses across answer options, rather than collapsing disagreement into a single consensus answer. However, existing LLM-based distribution prediction is often unstable and degrades under cultural and domain shift. Token score-based estimates can change with minor option wording or formatting, response sampling-based estimates are expensive and sensitive to prompts and decoding settings, and directly generated distributions are frequently miscalibrated.We propose Evi-DA, an evidence-based alignment technique that improves the fidelity and robustness of LLM-based distribution estimation under domain and cultural shift. Given a target country and a multiple-choice question, Evi-DA retrieves related World Values Survey items and their answer distributions, predicts a coarse Welzel value signature for each option, and infers the country-conditioned answer distribution in a structured format. We train the LLMs using a two-stage pipeline, where reinforcement learning optimizes survey-derived rewards that encourage accurate intermediate value predictions, faithful final distributions, well-formed structured outputs, and reduced cultural bias. Across in-domain and out-of-domain benchmarks and multiple open-source backbones, Evi-DA reduces Jensen-Shannon divergence between predicted and gold distributions relative to strong baselines, with average relative improvements of up to 44%.
Anthropogenic Regional Adaptation in Multimodal Vision-Language Model
Samuel Cahyawijaya | Peerat Limkonchotiwat | Tack Hwa Wong | Carlos Rafael Catalan | Manuel Antonio Rufino | Hitesh Laxmichand Patel | Amit Agarwal | Muhammad Reza Qorib | Vicky Feliren | Holy Lovenia | Aye Hninn Khine | Frederikus Hudi | David Anugraha | Alham Fikri Aji | Romrawin Chumpu | Viet Thanh Pham | Minghan Wang | Mohamed Fazli Mohamed Imam | Ruochen Zhang | Joseph Marvin Imperial | Khumaisa Nur’aini | Do Xuan Long | Musa Izzanardi Wijanarko | Joel Ruben Antony Moniz | Patrick Amadeus Irawan | Hanif Muhammad Zhafran | Isaiah Edri W. Flores | Salsabila Zahirah Pranida | Jun Kevin | Jostin Jerico Rosal | Patricia Nicole Monderin | Kun Kerdthaisong | Ahmad Mustafid | My Chiffon Nguyen | Natchapon Jongwiriyanurak | Siva Worajitwannakul | Haochen Li | Adrian Xuan Wei Lim | Bin Wang | Muhammad Ravi Shulthan Habibi | Lynnette Hui Xian Ng | Mithil Bangera | Yeshil Bangera | Priyaranjan Pattnayak | Dun Li Chan | Sherissa Caren Djuniwar | Cho Chan Myei Oo | Ming Shan Hee
Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026
Samuel Cahyawijaya | Peerat Limkonchotiwat | Tack Hwa Wong | Carlos Rafael Catalan | Manuel Antonio Rufino | Hitesh Laxmichand Patel | Amit Agarwal | Muhammad Reza Qorib | Vicky Feliren | Holy Lovenia | Aye Hninn Khine | Frederikus Hudi | David Anugraha | Alham Fikri Aji | Romrawin Chumpu | Viet Thanh Pham | Minghan Wang | Mohamed Fazli Mohamed Imam | Ruochen Zhang | Joseph Marvin Imperial | Khumaisa Nur’aini | Do Xuan Long | Musa Izzanardi Wijanarko | Joel Ruben Antony Moniz | Patrick Amadeus Irawan | Hanif Muhammad Zhafran | Isaiah Edri W. Flores | Salsabila Zahirah Pranida | Jun Kevin | Jostin Jerico Rosal | Patricia Nicole Monderin | Kun Kerdthaisong | Ahmad Mustafid | My Chiffon Nguyen | Natchapon Jongwiriyanurak | Siva Worajitwannakul | Haochen Li | Adrian Xuan Wei Lim | Bin Wang | Muhammad Ravi Shulthan Habibi | Lynnette Hui Xian Ng | Mithil Bangera | Yeshil Bangera | Priyaranjan Pattnayak | Dun Li Chan | Sherissa Caren Djuniwar | Cho Chan Myei Oo | Ming Shan Hee
Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026
While the field of vision-language (VL) has achieved remarkable success in integrating visual and textual information across multiple languages and domains, there is no dedicated framework for assessing human-centric alignment in vision-language systems.
We offer two contributions to address this gap. First, we introduce Anthropogenic Regional Adaptation: a regional-adaptation framework that aims to optimize model relevance to specific regional contexts while ensuring the retention of global generalization capabilities. Second, we present a simple, but effective adaptation method named Geographical-generalization-made-easy (GG-EZ), which utilizes regional data filtering and model merging.
Through comprehensive ablations on 3 VL architectures: large vision-language models (LVLM), text-to-image diffusion models, and vision-language embedding models, and a case study in Southeast Asia (SEA) regional adaptation, we demonstrate the importance of Anthropogenic Regional Adaptation and GG-EZ, showing 5-15% gains in cultural relevance metrics across SEA while maintaining over 98% of global performance and even occasionally surpassing it.
Our findings establish Anthropogenic Regional Alignment as a foundational paradigm towards applicability of multimodal VL architectures in diverse regions and demonstrate a simple-yet-effective baseline method that optimizes regional value alignment while preserving global generalization.
We offer two contributions to address this gap. First, we introduce Anthropogenic Regional Adaptation: a regional-adaptation framework that aims to optimize model relevance to specific regional contexts while ensuring the retention of global generalization capabilities. Second, we present a simple, but effective adaptation method named Geographical-generalization-made-easy (GG-EZ), which utilizes regional data filtering and model merging.
Through comprehensive ablations on 3 VL architectures: large vision-language models (LVLM), text-to-image diffusion models, and vision-language embedding models, and a case study in Southeast Asia (SEA) regional adaptation, we demonstrate the importance of Anthropogenic Regional Adaptation and GG-EZ, showing 5-15% gains in cultural relevance metrics across SEA while maintaining over 98% of global performance and even occasionally surpassing it.
Our findings establish Anthropogenic Regional Alignment as a foundational paradigm towards applicability of multimodal VL architectures in diverse regions and demonstrate a simple-yet-effective baseline method that optimizes regional value alignment while preserving global generalization.
Discourse Graph Guided Document Translation with Large Language Models
Viet Thanh Pham | Minghan Wang | Hao-Han Liao | Thuy-Trang Vu
Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Viet Thanh Pham | Minghan Wang | Hao-Han Liao | Thuy-Trang Vu
Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Adapting large language models to full document translation remains challenging due to the difficulty of capturing long-range dependencies and preserving discourse coherence throughout extended texts. While recent agentic machine translation systems mitigate context window constraints through multi-agent orchestration and persistent memory, they require substantial computational resources and are sensitive to memory retrieval strategies. We introduce TransGraph, a discourse-guided framework that explicitly models inter-chunk relationships through structured discourse graphs and selectively conditions each translation segment on relevant graph neighbourhoods rather than relying on sequential or exhaustive context. Across three document-level MT benchmarks spanning six languages and diverse domains, TransGraph consistently surpasses strong baselines in translation quality and terminology consistency while incurring significantly lower token overhead.
LiveCultureBench: a Multi-Agent, Multi-Cultural Benchmark for Large Language Models in Dynamic Social Simulations
Viet Thanh Pham | Lizhen Qu | Thuy-Trang Vu | Gholamreza Haffari | Dinh Phung
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Viet Thanh Pham | Lizhen Qu | Thuy-Trang Vu | Gholamreza Haffari | Dinh Phung
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Large language models (LLMs) are increasingly deployed as autonomous agents, yet evaluations focus primarily on task success rather than cultural appropriateness or evaluator reliability. We introduce LiveCultureBench, a multi-cultural, dynamic benchmark that embeds LLMs as agents in a simulated town and evaluates them on both task completion and adherence to socio-cultural norms. The simulation models a small city as a location graph with synthetic residents having diverse demographic and cultural profiles. Each episode assigns one resident a daily goal while others provide social context. An LLM-based verifier generates structured judgments on norm violations and task progress, which we aggregate into metrics capturing task-norm trade-offs and verifier uncertainty. Using LiveCultureBench across models and cultural profiles, we study (i) cross-cultural robustness of LLM agents, (ii) how they balance effectiveness against norm sensitivity, and (iii) when LLM-as-a-judge evaluation is reliable for automated benchmarking versus when human oversight is needed.
2025
CultureInstruct: Curating Multi-Cultural Instructions at Scale
Viet Thanh Pham | Zhuang Li | Lizhen Qu | Gholamreza Haffari
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Viet Thanh Pham | Zhuang Li | Lizhen Qu | Gholamreza Haffari
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Large language models, despite their remarkable success in recent years, still exhibit severe cultural bias. Therefore, in this paper, we introduce CultureInstruct, a large-scale instruction-tuning dataset designed to reduce cultural bias in LLMs. CultureInstruct is constructed with an automatic pipeline, utilizing public web sources and a specialized LLM to generate instruction. Our data comprises 430K instructions, ranging from classic NLP tasks to complex reasoning. CultureInstruct also covers 11 most relevant topics to cultural knowledge, making it highly diverse. Our experiments show that fine-tuning LLMs with CultureInstruct results in consistent improvements across three types of cultural benchmarks, including (i) general cultural knowledge, (ii) human opinions and values, and (iii) linguistic cultural bias. Our best model, Qwen2-Instruct 72B + CultureInstruct, outperforms GPT-4o Mini and GPT-4o with 18.47% and 13.07% average relative improvements on cultural benchmarks.
Proverbs Run in Pairs: Evaluating Proverb Translation Capability of Large Language Model
Minghan Wang | Viet Thanh Pham | Farhad Moghimifar | Thuy-Trang Vu
Findings of the Association for Computational Linguistics: ACL 2025
Minghan Wang | Viet Thanh Pham | Farhad Moghimifar | Thuy-Trang Vu
Findings of the Association for Computational Linguistics: ACL 2025
Despite achieving remarkable performance, machine translation (MT) research remains underexplored in terms of translating cultural elements in languages, such as idioms, proverbs, and colloquial expressions. This paper investigates the capability of state-of-the-art neural machine translation (NMT) and large language models (LLMs) in translating proverbs, which are deeply rooted in cultural contexts. We construct a translation dataset of standalone proverbs and proverbs in conversation for four language pairs. Our experiments show that the studied models can achieve good translation between languages with similar cultural backgrounds, and LLMs generally outperform NMT models in proverb translation. Furthermore, we find that current automatic evaluation metrics such as BLEU, CHRF++ and COMET are inadequate for reliably assessing the quality of proverb translation, highlighting the need for more culturally aware evaluation metrics.
SurveyPilot: an Agentic Framework for Automated Human Opinion Collection from Social Media
Viet Thanh Pham | Lizhen Qu | Zhuang Li | Suraj Sharma | Gholamreza Haffari
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Viet Thanh Pham | Lizhen Qu | Zhuang Li | Suraj Sharma | Gholamreza Haffari
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Opinion survey research is a crucial method used by social scientists for understanding societal beliefs and behaviors. Traditional methodologies often entail high costs and limited scalability, while current automated methods such as opinion synthesis exhibit severe biases and lack traceability. In this paper, we introduce SurveyPilot, a novel finite-state orchestrated agentic framework that automates the collection and analysis of human opinions from social media platforms. SurveyPilot addresses the limitations of pioneering approaches by (i) providing transparency and traceability in each state of opinion collection and (ii) incorporating several techniques for mitigating biases, notably with a novel genetic algorithm for improving result diversity. Our extensive experiments reveal that SurveyPilot achieves a close alignment with authentic survey results across multiple domains, observing average relative improvements of 68,98% and 51,37% when comparing to opinion synthesis and agent-based approaches. Implementation of SurveyPilot is available on https://github.com/thanhpv2102/SurveyPilot.
2024
Multi-Cultural Norm Base: Frame-based Norm Discovery in Multi-Cultural Settings
Viet Thanh Pham | Shilin Qu | Farhad Moghimifar | Suraj Sharma | Yuan-Fang Li | Weiqing Wang | Reza Haf
Proceedings of the 28th Conference on Computational Natural Language Learning
Viet Thanh Pham | Shilin Qu | Farhad Moghimifar | Suraj Sharma | Yuan-Fang Li | Weiqing Wang | Reza Haf
Proceedings of the 28th Conference on Computational Natural Language Learning
Sociocultural norms serve as guiding principles for personal conduct in social interactions within a particular society or culture. The study of norm discovery has seen significant development over the last few years, with various interesting approaches. However, it is difficult to adopt these approaches to discover norms in a new culture, as they rely either on human annotations or real-world dialogue contents. This paper presents a robust automatic norm discovery pipeline, which utilizes the cultural knowledge of GPT-3.5 Turbo (ChatGPT) along with several social factors. By using these social factors and ChatGPT, our pipeline avoids the use of human dialogues that tend to be limited to specific scenarios, as well as the use of human annotations that make it difficult and costly to enlarge the dataset. The resulting database - Multi-cultural Norm Base (MNB) - covers 6 distinct cultures, with over 150k sociocultural norm statements in total. A state-of-the-art Large Language Model (LLM), Llama 3, fine-tuned with our proposed dataset, shows remarkable results on various downstream tasks, outperforming models fine-tuned on other datasets significantly.
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- Gholamreza Haffari 4
- Lizhen Qu 4
- Zhuang Li 3
- Thuy-Trang Vu 3
- Minghan Wang 3
- Farhad Moghimifar 2
- Suraj Sharma 2
- Amit Agarwal 1
- Alham Fikri Aji 1
- David Anugraha 1
- Mithil Bangera 1
- Yeshil Bangera 1
- Samuel Cahyawijaya 1
- Carlos Rafael Catalan 1
- Dun Li Chan 1
- Romrawin Chumpu 1
- Sherissa Caren Djuniwar 1
- Vicky Feliren 1
- Isaiah Edri W. Flores 1
- Muhammad Ravi Shulthan Habibi 1
- Reza Haf 1
- Ming Shan Hee 1
- Frederikus Hudi 1
- Mohamed Fazli Mohamed Imam 1
- Joseph Marvin Imperial 1
- Patrick Amadeus Irawan 1
- Natchapon Jongwiriyanurak 1
- Kun Kerdthaisong 1
- Jun Kevin 1
- Aye Hninn Khine 1
- Haochen Li 1
- Yuan-Fang Li 1
- Hao-Han Liao 1
- Adrian Xuan Wei Lim 1
- Peerat Limkonchotiwat 1
- Do Xuan Long 1
- Holy Lovenia 1
- Patricia Nicole Monderin 1
- Joel Ruben Antony Moniz 1
- Ahmad Mustafid 1
- Lynnette Hui Xian Ng 1
- My Chiffon Nguyen 1
- Khumaisa Nur’aini 1
- Cho Chan Myei Oo 1
- Hitesh Laxmichand Patel 1
- Priyaranjan Pattnayak 1
- Dinh Phung 1
- Salsabila Zahirah Pranida 1
- Muhammad Reza Qorib 1
- Shilin Qu 1
- Jostin Jerico Rosal 1
- Manuel Antonio Rufino 1
- Bin Wang 1
- Weiqing Wang 1
- Musa Izzanardi Wijanarko 1
- Tack Hwa Wong 1
- Siva Worajitwannakul 1
- Hanif Muhammad Zhafran 1
- Ruochen Zhang 1