supertone-inc/supertonic
Supertonic
Supertonic is an on-device neural text-to-speech engine that runs entirely locally without cloud dependencies or GPU acceleration. It converts written text into natural-sounding speech across 31 languages with automatic language detection and a fallback model for unsupported locales.
The engine provides expressive speech control through inline prosody tags that dynamically adjust pitch, rate, and tone during synthesis. It supports voice cloning from a short reference audio clip by extracting a speaker embedding vector, and offers a selection of pre-built voices tuned for different use cases. Synthesis quality and playback speed are configurable, allowing trade-offs between latency and audio fidelity.
Supertonic includes a local HTTP server that exposes an endpoint compatible with the OpenAI Audio Speech API specification for drop-in integration with external tools and applications. A command-line interface is also available for generating audio files directly from text with configurable voice, quality, language, and style parameters. The engine applies rule-based and ML-based text normalization for numbers, dates, currencies, and units across supported languages.
