Building from scratch: a multi-agent framework with human-in-the-loop for multilingual legal terminology mapping

Accurately mapping legal terminology across languages remains a significant challenge, especially for language pairs like Chinese and Japanese, which share a large number of homographs with different meanings. Existing resources and standardized tools for these languages are limited. To address this, we propose a human-AI collaborative approach for building a multilingual legal terminology database, based on a multi-agent framework. This approach integrates advanced large language models (LLMs) and legal domain experts throughout the entire process—from raw document preprocessing, article-level alignment, to terminology extraction, mapping, and quality assurance. Unlike a single automated pipeline, our approach places greater emphasis on how human experts participate in this multi-agent system. Humans and AI agents take on different roles: AI agents handle specific, repetitive tasks, such as OCR, text segmentation, semantic alignment, and initial terminology extraction, while human experts provide crucial oversight, review, and supervise the outputs with contextual knowledge and legal judgment. We tested the effectiveness of this framework using a trilingual parallel corpus comprising 35 key Chinese statutes, along with their English and Japanese translations. The experimental results show that this human-in-the-loop, multi-agent workflow not only improves the precision and consistency of multilingual legal terminology mapping but also offers greater scalability compared to traditional manual methods. Additionally, we observed that several open-source large language models performed exceptionally well in legal terminology extraction, demonstrating their cost-effectiveness and potential for sustainable applications in multilingual legal natural language processing (NLP). Finally, the open, extensible platform we developed supports continuous expert curation and can be easily integrated into various legal translation, research, and AI-powered knowledge management tools.