Comparative analysis of Ukrainian speech recognition models Whsiper and Vosk

This paper presents a comparative analysis of two approaches to automatic speech recognition (ASR) — the Whisper transformer architecture and the Kaldi-based Vosk solution — with a focus on Ukrainian language recognition. The study is based on experiments performed using two benchmarks: faster-whisper on GPU and local Vosk models on CPU. The evaluation was performed using standard metrics: Word Error Rate (WER) to measure accuracy and Real-Time Factor (RTF) and average processing time to assess performance. Before comparison, the texts were normalized (punctuation removal, conversion to lower case, removal of extra spaces) to ensure correct WER calculation. The results show that, when hardware accelerated, Whisper demonstrates lower WER values and significantly better throughput compared to Vosk on CPU, especially for the medium and large-v3 models. Instead, Vosk proves its competitiveness in resource-constrained scenarios: it consumes less memory, is stable and deterministic in repeated runs, which makes it suitable for embedded and offline solutions. The paper also discusses the limitations of the study, including the small test dataset and the dependence of the results on the hardware parameters and decoding settings. Based on the conclusions obtained, practical recommendations for choosing an architecture are formulated: for services where GPUs are available and critical accuracy is critical, Whisper of medium/large size is recommended; for autonomous systems with limited resources, Vosk. Further research requires expanded datasets, adaptation of models to local vocabulary, and a full analysis of hybrid deployment options