We examine how the capabilities of large language models (LLMs) have evolved on eight Belarusian language tasks contributed in 2023 to OpenAI’s Evals framework. We evaluate state-of-the-art models both on the original development sets and newly created test sets. Results demonstrate significant but non-uniform progress over this period: some tasks are almost saturated, while others show minor improvement beyond trivial baselines. Error analysis shows that certain challenges haven’t yet been addressed, e.g. misidentification of non-words as legitimate vocabulary, or conversion from modern to classical orthography. We release the datasets and the generated completions (https://doi.org/10.5281/zenodo.18163825).

In the epoch of multilingual large language models (LLMs), it is still challenging to evaluate the models’ understanding of lower-resourced languages, which motivates further development of expert-crafted natural language understanding benchmarks. We introduce BelarusianGLUE — a natural language understanding benchmark for Belarusian, an East Slavic language, with ≈15K instances in five tasks: sentiment analysis, linguistic acceptability, word in context, Winograd schema challenge, textual entailment. A systematic evaluation of BERT models and LLMs against this novel benchmark reveals that both types of models approach human-level performance on easier tasks, such as sentiment analysis, but there is a significant gap in performance between machine and human on a harder task — Winograd schema challenge. We find the optimal choice of model type to be task-specific: e.g. BERT models underperform on textual entailment task but are competitive for linguistic acceptability. We release the datasets (https://hf.co/datasets/maaxap/BelarusianGLUE) and evaluation code (https://github.com/maaxap/BelarusianGLUE).