Aligning Language Models for Icelandic Legal Text Summarization
Þórir Hrafn Harðarson, Hrafn Loftsson, Stefán Ólafsson
TL;DR
This work investigates aligning Icelandic legal text summarization with domain-specific language standards using preference-based training. By combining domain-focused pretraining, instruction fine-tuning, and methods such as Direct Preference Optimization (DPO) and Reinforcement Learning from Human Feedback (RLHF), the study shows that preference training can improve legal accuracy but does not consistently enhance general Icelandic language quality. The results also reveal a disconnect between automated metrics (e.g., ROUGE) and human expert judgments, underscoring the need for qualitative evaluation in legal NLP. The findings highlight the importance of language-specific pre-training and suggest future work in retrieval-augmented generation and larger, more diverse datasets to achieve practically reliable Icelandic legal text summarization.
Abstract
The integration of language models in the legal domain holds considerable promise for streamlining processes and improving efficiency in managing extensive workloads. However, the specialized terminology, nuanced language, and formal style of legal texts can present substantial challenges. This study examines whether preference-based training techniques, specifically Reinforcement Learning from Human Feedback and Direct Preference Optimization, can enhance models' performance in generating Icelandic legal summaries that align with domain-specific language standards and user preferences. We compare models fine-tuned with preference training to those using conventional supervised learning. Results indicate that preference training improves the legal accuracy of generated summaries over standard fine-tuning but does not significantly enhance the overall quality of Icelandic language usage. Discrepancies between automated metrics and human evaluations further underscore the importance of qualitative assessment in developing language models for the legal domain.
