The Blizzard Challenge 2025

The nineteenth Blizzard Challenge focused on speech synthesis for Bildts, a low resource language variety in the Netherands with approximately 6,000 native slpeakers. The main task provided a single-speaker 7-hour Bildts dataset and required<br/>participants to build a voice from this dataset, restricted to using only publicly available data and pre-trained models. Listeners evaluated synthesised samples for Bildts-likeness, naturalness, appropriateness, overall signal quality, and word-level quality (using RPT-like feedback). The optional zero-shot task provided 10 seconds of reference speech from two speakers; participants built voices matching these speakers without constraints on data or models. Listeners evaluated the main task for Bildts-likeness, naturalness, appropriateness, overall signal quality, and word-level errors, while the zero-shot task focused on Bildts-likeness and speaker similarity. Seven teams participated in the main task and five in the zero-shot task.