Google has introduced Gemini 3.1 Flash TTS, a preview text-to-speech model focused on improving speech quality, expressive control, and multilingual generation. Unlike previous iterations that prioritized simple conversion, this release emphasizes natural-language audio tags, native support for more than 70 languages, and native multi-speaker dialogue.

This release signals a shift from ‘black-box’ audio generation toward a more granular, instruction-based workflow. The model is rolling out in preview through the Gemini API and Google AI Studio, on Vertex AI for enterprises, and via Google Vids for Workspace users.

Speech Quality, Control, and Developer Workflow

The standout technical achievement of Gemini 3.1 Flash TTS is its performance on industry benchmarks. The model currently reports an Artificial Analysis TTS leaderboard Elo score of 1,211, positioning it as Google’s most natural and expressive speech model to date.

Beyond raw quality, the update introduces a more sophisticated control layer for AI developers. Instead of relying on static configurations, developers can now use audio tags and natural-language prompting to steer the following:

• Style and Tone: Instructing the model to shift delivery based on the context of the scene.
• Pacing and Delivery: Directing the rhythm and emphasis of the speech to match specific narrative needs.
• Accent and Dialect: Leveraging localized nuances within the 70+ supported languages.

Native Multi-Speaker Dialogue

A key differentiator for Gemini 3.1 Flash TTS is its support for native multi-speaker dialogue. Traditional TTS pipelines often require separate API calls for different voices, which can lead to disjointed pacing. By handling multiple speakers natively, the model maintains a more natural conversational flow, making it particularly useful for developers building podcasts, dramatic scripts, or collaborative assistant interfaces.

Security and Identification: SynthID Watermarking

As generative audio reaches higher levels of fidelity, the ability to identify AI-generated content becomes a technical necessity. Google has integrated SynthID watermarking across all audio generated by Gemini 3.1 Flash TTS.

The implementation of SynthID is designed with two priorities:

1. Imperceptibility: The watermark is embedded in a way that does not degrade the listener’s audio experience.
2. Reliable Detection: The watermark enables the identification of AI-generated content, assisting in the prevention of misinformation and ensuring transparency in digital ecosystems.

Technical Summary

Feature	Specification
Model	Gemini 3.1 Flash TTS (Preview)
Elo Score	1,211 (Artificial Analysis TTS Leaderboard)
Language Support	70+ Languages
Core Features	Audio tags, Natural-language control, Multi-speaker dialogue
Safety	Integrated SynthID Watermarking
Platforms	Gemini API, AI Studio, Vertex AI, Google Vids

Overall, Gemini 3.1 Flash TTS represents a move toward a more ‘authorial’ approach to audio AI. By combining high benchmark performance with granular natural-language controls, Google AI team is providing the tools to build voice experiences that feel less like synthesized output and more like directed performances.

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Check out the Technical details, For developers in preview available now on Gemini API and Google AI Studio, For enterprises in preview on Vertex AI, and For Workspace users via Google Vids . Also, feel free to follow us on Twitter and don’t forget to join our 130k+ ML SubReddit and Subscribe to our Newsletter. Wait! are you on telegram? now you can join us on telegram as well.

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