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TTS (Text-to-Speech)

Definition

AI technology that converts written text into natural-sounding spoken audio.

Why It Matters

TTS turns text into spoken audio, the inverse of STT. Modern neural TTS produces voices indistinguishable from real recordings on short utterances, which unlocks audiobook generation, voice-overs, screen readers for visually impaired users, and dubbing without paid voice actors.

Key Points

  • Modern TTS approaches: vocoder-based (FastSpeech2 + HiFi-GAN), end-to-end (VITS, XTTS v2), and LLM-based (Bark, Parler-TTS).
  • XTTS v2: voice cloning from 3 seconds of reference audio. Open-source, Apache 2.0 license.
  • Mean Opinion Score (MOS): human naturalness rating 1–5. Best neural TTS scores 4.3–4.7; natural human speech averages ~4.5.
  • Streaming TTS systems target 200–500 ms time-to-first-audio to feel real-time in conversational dialogue applications.
  • SSML (Speech Synthesis Markup Language) controls emphasis, pauses, pronunciation and speaking rate in supported engines, useful for audiobooks and voice agents.

Example

Kokoro, OuteTTS, Piper and ElevenLabs are TTS engines. Kokoro generates a 30-second clip in about 1 second on a consumer GPU and supports 20+ voices across 8 languages. Output is plain WAV or MP3, ready to drop into any audio pipeline.

Common Misconception

Voice cloning quality degrades sharply with noisy reference audio. A 3-second sample recorded in a noisy environment or over a phone call produces a noticeably inferior clone compared to a clean recording. Longer reference clips help but cannot fully compensate for poor audio quality.

Related Terms

  • STT (Speech-to-Text)AI technology that converts spoken audio into written text. Also called ASR (Automatic Speech Recognition).
  • Multimodal AIAI models that can process multiple types of input, text, images, audio, video.
  • Open Source AIAI models released with open licenses (MIT, Apache 2.0) allowing anyone to use, modify and deploy them.

TTS (Text-to-Speech) on Rewind.ai

Rewind.ai's voice tool runs Kokoro for free TTS (20+ voices, 8 languages) and premium engines for the rest. Speed and pitch sliders work on every voice; SSML markup is supported where the engine allows it.

Explore the Tools

Quick Facts

TermTTS (Text-to-Speech)
RelatedSTT (Speech-to-Text), Multimodal AI, Open Source AI

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FAQ

TTS (Text-to-Speech) on Rewind.ai is a free AI tool. There's no charge and no sign up needed to start.

Yes. You get 2,500 free tokens per day to use TTS (Text-to-Speech) and every other tool on Rewind.ai. A free account raises that to 5,000 tokens/day. You can buy more starting at $1.

TTS (Text-to-Speech) runs open-source AI models on our GPU servers. Send your request and the result comes back in seconds.

No. You can use TTS (Text-to-Speech) right away without signing up. A free account doubles your daily usage to 5,000 tokens and saves your history.

Anonymous users get 2,500 tokens/day. Free accounts get 5,000 tokens/day. Tokens reset every 24 hours. Each generation costs ~100-5,000 tokens depending on the operation.

Your data is processed on our servers and isn't stored permanently unless you choose to save it. We don't sell or share it.

Yes. Content from TTS (Text-to-Speech) is yours to use for personal or commercial work. The AI models we run are commercially licensed.

TTS (Text-to-Speech) matches the quality of paid services because it runs the latest open-source AI models. The difference is you don't pay per use.

TTS (Text-to-Speech) runs open-source AI models including Qwen 2.5, FLUX and Whisper. We update to newer models as they ship.

Yes. TTS (Text-to-Speech) works in any mobile browser, and the layout adapts to your screen size.

Sign up for a free account to get 5,000 tokens/day, double the anonymous limit. Or buy token packs starting at $5 for 200,000 tokens. See /pricing/ for all options.

Yes. After you generate content, you can download it, copy it, or share it via a unique link. Signed-in users can also view their generation history.

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