Google Launches Gemini 3.1 Flash TTS with Audio Tags for AI Voice Control

Google rolled out Gemini 3.1 Flash TTS on April 15, 2026, making its most expressive text-to-speech model available to developers through the Gemini API and Google AI Studio, enterprises via Vertex AI, and Workspace users through Google Vids.

The model scored an Elo rating of 1,211 on the Artificial Analysis TTS leaderboard, which tracks blind human preferences across thousands of comparisons. That benchmark also placed 3.1 Flash TTS in its “most attractive quadrant” for balancing speech quality against cost—a metric that matters for companies running voice applications at scale.

Audio Tags Change the Game

The standout feature here is audio tags. Developers can now embed natural language commands directly into text input to control vocal style, pacing, and delivery mid-sentence. Think of it as directing a voice actor through script annotations rather than recording multiple takes.

Google AI Studio now offers what the company calls a “director’s chair” setup with three main controls. Scene direction lets developers define environment context so AI voices stay in character across dialogue turns. Speaker-level settings allow casting unique Audio Profiles with specific pace, tone, and accent parameters. And inline tags can override these settings on the fly—useful for emotional shifts within a single line.

Once configurations work in the playground, developers can export them as Gemini API code for consistent deployment across platforms.

Global Reach with 70+ Languages

The model supports more than 70 languages with the same style and accent controls available in English. For companies building localized voice experiences, this means one API call can handle markets from São Paulo to Seoul without sacrificing expressivity.

Native multi-speaker dialogue comes built in, eliminating the need to stitch together separate voice generations for conversations. Early testers have highlighted this as particularly useful for audiobook production and interactive content.

SynthID Watermarking Baked In

Every audio output carries a SynthID watermark—an imperceptible signature woven into the audio that allows detection of AI-generated content. Google positions this as a misinformation safeguard, though it also provides provenance tracking for enterprises concerned about content authenticity.

This launch follows Google’s March releases in the Gemini 3.1 family. Flash-Lite arrived on March 3 targeting low-latency, high-volume applications. Flash Live dropped on March 26 with bidirectional audio streaming and interruption handling for real-time voice agents.

Developers can start testing immediately in the Google AI Studio Playground, with enterprise access available through Vertex AI console. The pricing structure that earned the “attractive quadrant” designation suggests Google is positioning this for production workloads, not just experimentation.

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