Google Launches Gemini 3.1 Flash TTS: AI Voice in 70+ Languages With Audio Tags

Google's Gemini 3.1 Flash TTS Redefines What AI Voice Can Do

On April 15, 2026, Google launched Gemini 3.1 Flash TTS — a new text-to-speech model that arrives with a genuinely differentiated feature set: audio tag-based control over vocal style and pacing, native multi-speaker dialogue generation, and broad multilingual coverage spanning over 70 languages. The model is live now through the Gemini API, Google AI Studio, Vertex AI, and Google Workspace Vids.

For anyone building applications that involve voice — podcasts, assistants, narration, accessibility tools — Gemini 3.1 Flash TTS represents a meaningful step forward in what developer-accessible AI voice generation can accomplish.

Audio Tags: Granular Control Over How AI Speaks

The standout capability in Gemini 3.1 Flash TTS is the audio tag system. Rather than selecting from preset voices or limited style controls, developers can embed natural-language control directives directly into their text prompts, specifying vocal character, delivery pace, and emotional tone at a granular level.

This is qualitatively different from standard TTS parameter tuning. Audio tags make voice control compositional — the same model can produce a calm, measured narrator for documentary-style content, a conversational peer for an AI assistant, or a dramatically paced presenter for an educational explainer, all through in-prompt instruction rather than model switching. The practical result for developers is significant flexibility without the engineering overhead of managing multiple voice models.

What Audio Tags Enable in Practice

- **Vocal style control**: Specify warmth, authority, enthusiasm, or calm through natural language

- **Pacing and rhythm**: Direct the model to speak quickly, pause deliberately, or slow for emphasis

- **Delivery character**: Instruct dramatic inflection, professional neutrality, or casual approachability

- **Per-segment customization**: Apply different tags to different sections within a single generation pass

Native Multi-Speaker Dialogue

Native multi-speaker dialogue generation is the second major AI voice capability worth highlighting. Gemini 3.1 Flash TTS can generate realistic back-and-forth conversations between multiple speakers in a single generation pass, maintaining natural conversational flow without requiring developers to stitch together separate single-speaker outputs.

This matters for use cases that previously required considerable audio engineering workarounds: podcast generation, multi-character story narration, interview formats, and any application where natural dialogue rhythm is essential. The model manages speaker transitions, conversational timing, and voice differentiation internally — significantly simplifying the developer workflow for dialogue-heavy audio applications.

70+ Languages and SynthID Watermarking

Gemini 3.1 Flash TTS supports over 70 languages, making it broadly deployable for international applications. The multilingual coverage spans major world languages with full audio tag and multi-speaker support — not just baseline transcription quality.

All audio generated by Gemini 3.1 Flash TTS is automatically watermarked using Google's SynthID system. SynthID embeds an imperceptible watermark directly into the audio signal that survives common processing operations like compression and format conversion. For developers building voice content pipelines, SynthID watermarking provides a responsible AI disclosure mechanism that does not compromise audio quality or user experience — an increasingly important consideration as AI-generated audio becomes more widely deployed.

Performance and Availability

On the Artificial Analysis TTS leaderboard, Gemini 3.1 Flash TTS achieved an Elo score of 1,211, placing it in the benchmark's top tier for the combination of speech quality and cost-efficiency. Google positions it in the "most attractive quadrant" — high-quality output at a price point that makes it economically viable at scale.

Access is available now through the Gemini API and Google AI Studio for developers, Vertex AI for enterprise deployments, and Google Workspace Vids for productivity applications. The breadth of distribution channels means Gemini 3.1 Flash TTS is accessible to individual developers building their first voice feature and to large-scale enterprise teams requiring production-grade AI voice infrastructure alike.

Sources: Google Blog (April 15, 2026), MarkTechPost (April 15, 2026), SiliconAngle (April 15, 2026), Google DeepMind Model Card (April 2026), Artificial Analysis TTS Leaderboard (April 2026)