Finetuning LLMs for EvaCun 2025 token prediction shared task
Josef Jon, Ondřej Bojar
TL;DR
This work tackles token prediction for cuneiform-origin languages (Akkadian and Sumerian) by fine-tuning autoregressive LLMs on the EvaCun 2025 task data using three prompt-based formulations. The authors implement a purely engineering baseline with three models (Aya Expanse 8B, Command-R 34B, Mistral Small 24B) and compare prompts All, One by One, and Restore, evaluating on a held-out dev set. They report that the best single-model performance reaches around 22.1% accuracy, while ensembling via majority voting raises accuracy to about 26.9%, highlighting both the feasibility and limitations of LLM-based token restoration for these ancient languages. The study provides a solid baseline for future, more language-informed approaches and suggests directions toward direct translation of cuneiform or visual-reading LLMs, given dataset biases and repetitiveness. Overall, it demonstrates that prompt-based fine-tuning of autoregressive LLMs can yield meaningful token restoration performance and sets a benchmark for future improvements in cuneiform NLP.
Abstract
In this paper, we present our submission for the token prediction task of EvaCun 2025. Our sys-tems are based on LLMs (Command-R, Mistral, and Aya Expanse) fine-tuned on the task data provided by the organizers. As we only pos-sess a very superficial knowledge of the subject field and the languages of the task, we simply used the training data without any task-specific adjustments, preprocessing, or filtering. We compare 3 different approaches (based on 3 different prompts) of obtaining the predictions, and we evaluate them on a held-out part of the data.
