Greek text to speech system improves with small curated audiobook data
Deterministic Prompting for Speaker-Stable Low-Resource Greek TTS
SoundComputation and LanguageMachine Learning
Summary
Making computers speak in Greek sounds nearly as good as a human even when there's only a little clean speech to learn from. The authors turned audiobook recordings into good quality training data using special alignment tools. They adapted a large speech model trained on multiple languages to Greek, fixing issues where the voice would change unexpectedly by using consistent prompts and a fine-tuning step that keeps the speaker’s identity. Their system speaks clearly and naturally, close to human voices, using only a few hours of single-speaker recordings.
What this means in practice
- •For voice assistant developers: Create Greek voices with consistent speaker identity using limited high-quality speech data.
- •For audiobook producers: Convert existing Greek audiobook recordings into reliable TTS training data for voice cloning.
Authors
Georgios Syllas, Efthymios Georgiou, Kosmas Kritsis, Alexandros Potamianos
Abstract
Modern TTS systems approach human quality for high-resource languages but degrade when clean speech data is scarce. Modern Greek exemplifies this, lacking the curated corpora behind state-of-the-art synthesis. We propose a data curation recipe that transforms audiobook recordings into TTS-ready data via WhisperX alignment and filtering. Then we fine-tune Parler-TTS (880M), a prompt-based multilingual model whose pre-training encodes phonetic priors transferable to Greek. During development, we find that LLM-generated style prompts introduce speaker drift at inference. Replacing them with deterministic prompts resolves this, and a speaker-specific LoRA stage trained on 3.5 h of single-speaker data anchors identity while updating ~5% of parameters. Our system achieves WER 10.7% (2.9 above the ASR floor), MOS-I 4.00 (vs. 4.36 human speech), and near-human speaker consistency (MOS-C 4.24 vs. 4.30), showing that robust single-speaker Greek TTS is achievable with limited curated data.