Flavio Bertini
Author directory2026
Gold-Preserving Synthetic Augmentation for Verbatim Swedish Automatic Speech Recognition
Giuseppe Chiriatti | Dimitrios Kokkinakis | Flavio Bertini | Ricardo Muñoz Sánchez | Herbert Lange
The Proceedings of Speech and Audio Language Models Workshop (2nd Edition)
Giuseppe Chiriatti | Dimitrios Kokkinakis | Flavio Bertini | Ricardo Muñoz Sánchez | Herbert Lange
The Proceedings of Speech and Audio Language Models Workshop (2nd Edition)
Verbatim transcripts, which keep the hesitations and interactional particles that ordinary automatic speech recognition (ASR) removes, are a prerequisite for speech-based cognitive assessment, and they are hardest to obtain for languages with little annotated speech. We study this problem for Swedish with a 1.02-hour corpus of manually transcribed spontaneous speech, too small for full fine-tuning of KB-Whisper-large. We adapt the model with a low-rank adapter and compare three ways of extending the training data: pseudo-labeling of untranscribed in-domain audio, unguided synthesis with a language model and a text-to-speech system, and a gold-preserving pipeline that reproduces the disfluency distribution of the gold corpus by construction and can be audited before training. Fine-tuning reduces disfluency-segment word error rate (WER) by 32% relative, with blockwise-bootstrap confidence intervals disjoint from the zero-shot baseline, while the three augmentation strategies are not separable by WER across five seeds. The gold-preserving pipeline needs no untranscribed audio, and its disfluency distribution can be verified in advance.