Gemini 3.1 Flash TTS
Gemini 3.1 Flash TTS is Google’s latest text-to-speech model designed to deliver highly expressive, controllable, and scalable AI-generated speech for developers and enterprises. Available in Google AI Studio and Gemini Enterprise Agent Platform, it focuses on precise control over how audio is generated, allowing users to shape delivery through natural language prompts and an extensive system of more than 200 audio tags that define pacing, tone, emotion, and style. It supports over 70 languages and regional variants, along with a library of 30 prebuilt voices, enabling users to generate speech ranging from professional narration to conversational or stylized performances. Developers can embed instructions directly into text inputs to guide vocal expression, combining pacing, emotion, and pauses in a structured prompting framework that produces nuanced, high-fidelity audio output. Gemini 3.1 Flash TTS is optimized for real-world applications.
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Eleven v4
Eleven v4 is a text-to-speech model from ElevenLabs for generating expressive spoken audio from written scripts. It supports multi-speaker dialogue, emotional direction and audio-event tags, voice cloning, and consistent speaker identity across generated scenes. Creators, publishers, and production teams can use it for narration, audiobooks, character dialogue, video and game voiceovers, and multilingual projects. Developers can generate speech through the ElevenLabs web application or API; the related Eleven v4 Turbo model is intended for real-time speech and voice-agent scenarios. Eleven v4 supports 90+ languages. A free plan includes monthly credits for personal use, while paid plans provide higher credit limits and additional features.
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Gemini 3.8 Flash TTS
Gemini 3.8 Flash TTS is Google’s expressive text-to-speech model for creating custom voices, directed performances, and multilingual audio experiences. The model can generate original voices from natural-language prompts by specifying characteristics such as role, accent, tone, pacing, and vocal style across more than 100 languages and dialects. Users can also replicate an authorized voice from a short audio sample, with consent verification, SynthID watermarking, and C2PA credentials supporting responsible voice creation. Gemini 3.8 Flash TTS provides line-by-line performance control, long-form speech generation, two-speaker scene staging, and support for nonverbal cues such as laughs, sighs, gasps, and conversational backchanneling. It is suited to use cases including games, audiobooks, podcasts, dubbing, interactive voice agents, branded audio, and media localization.
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Gradium
Gradium is a voice AI platform for developers and organizations building speech-enabled applications and conversational agents. Its hosted APIs provide streaming text-to-speech, speech-to-text, speech translation, and speech-to-speech, with WebSocket and REST interfaces, real-time turn detection, pronunciation controls, and voice design or cloning features. A browser-based studio lets users try the models and manage voices, while documentation and SDK guides support application development. Use cases include voice agents, customer-service automation, live transcription, multilingual voice experiences, and spoken content generation. Gradium also publishes Phonon, an open-weight text-to-speech model designed for local, offline use in applications and on-device systems. Plans use credits for speech generation, transcription, and translation.
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