Fish Audio Open-Sources S2: Expressive Text-to-Speech with Natural Language Control and 100ms Latency

Fish Audio's S2 model brings a major shift in locally-deployable speech synthesis: open-source, expressive TTS with intuitive natural language control. Users can direct emotional inflection and delivery using tags like [whispers sweetly] or [laughing nervously], and the model generates multi-speaker dialogue sequences in a single forward pass—eliminating the need for sequential invocations and dramatically reducing latency.

For practitioners building local LLM-based applications, S2 addresses a critical gap: integrating high-quality, controllable speech output without dependency on proprietary APIs. At 100ms time-to-first-audio, it's viable for interactive and real-time applications. Support for 80+ languages makes it globally deployable, and the open-source release means full transparency and fine-tuning capability. This is particularly valuable for building complete local AI pipelines that combine text generation, reasoning, and naturalistic voice output entirely on-device.

Source: r/LocalLLaMA · Relevance: 8/10