---
name: ai-voice-cloning
description: Generate natural AI voices, text-to-speech, and voice synthesis using the inference.sh CLI with models like Inworld TTS, ElevenLabs, and Kokoro TTS for voiceovers, audiobooks, podcasts, and more.
---

> **Install the belt CLI skill:** `npx skills add belt-sh/cli`

# AI Voice Generation

Generate natural AI voices via [inference.sh](https://inference.sh) CLI.

![AI Voice Generation](https://cloud.inference.sh/u/4mg21r6ta37mpaz6ktzwtt8krr/01jz00krptarq4bwm89g539aea.png)

## Quick Start

> Requires inference.sh CLI (`belt`). [Install instructions](https://raw.githubusercontent.com/inference-sh/skills/refs/heads/main/cli-install.md)

```bash
belt login

# Generate speech
belt app run infsh/kokoro-tts --input '{
  "prompt": "Hello! This is an AI-generated voice that sounds natural and engaging.",
  "voice": "af_sarah"
}'
```


## Available Models

| Model | App ID | Best For |
|-------|--------|----------|
| **Inworld TTS-2** | `inworld/text-to-speech-2` | **100+ languages, emotion/non-verbal steering, delivery modes** |
| Inworld TTS 1.5 Max | `inworld/text-to-speech-1-5-max` | Low latency (<200ms), 15 languages |
| Inworld TTS 1.5 Mini | `inworld/text-to-speech-1-5-mini` | Ultra-low latency (~120ms), 15 languages, real-time |
| ElevenLabs TTS | `elevenlabs/tts` | Premium quality, 22+ voices, 32 languages |
| ElevenLabs Voice Changer | `elevenlabs/voice-changer` | Transform existing voice recordings |
| Kokoro TTS | `infsh/kokoro-tts` | Natural, multiple voices |
| DIA | `infsh/dia-tts` | Conversational, expressive |
| Chatterbox | `infsh/chatterbox` | Casual, entertainment |
| Higgs | `infsh/higgs-tts` | Professional narration |
| VibeVoice | `infsh/vibevoice` | Emotional range |

## Kokoro Voice Library

### American English

| Voice ID | Gender | Style |
|----------|--------|-------|
| `af_sarah` | Female | Warm, friendly |
| `af_nicole` | Female | Professional |
| `af_sky` | Female | Youthful |
| `am_michael` | Male | Authoritative |
| `am_adam` | Male | Conversational |
| `am_echo` | Male | Clear, neutral |

### British English

| Voice ID | Gender | Style |
|----------|--------|-------|
| `bf_emma` | Female | Refined |
| `bf_isabella` | Female | Warm |
| `bm_george` | Male | Classic |
| `bm_lewis` | Male | Modern |

## Inworld TTS — Character & Emotion Voices

Inworld TTS-2 is purpose-built for character voices, gaming, and expressive speech. Use `[brackets]` inline for emotion, non-verbals, and delivery control:

```bash
# Expressive character voice with emotion steering
belt app run inworld/text-to-speech-2 --input '{
  "text": "[excited] Oh wow, you actually found the ancient artifact! [gasp] I cannot believe it... [whisper] We need to keep this between us.",
  "voice_id": "Sarah",
  "delivery_mode": "CREATIVE"
}'

# Calm narrator with stable delivery
belt app run inworld/text-to-speech-2 --input '{
  "text": "The sun set behind the mountains, casting long shadows across the valley. A new chapter was about to begin.",
  "voice_id": "Sarah",
  "delivery_mode": "STABLE"
}'
```

**Delivery modes:** `STABLE` (consistent, narration), `BALANCED` (natural, default), `CREATIVE` (expressive, characters)

**Steering examples:** `[laugh]`, `[sigh]`, `[whisper]`, `[excited]`, `[sad]`, `[angry]`, `[pause]`, `[gasp]`

**Built-in voices** (271+ across 15 languages): `Sarah`, `Alex`, `Ashley`, `Dennis`, `Hana`, `Blake`, `Luna`, `Clive`, and many more. Browse all at the [Inworld TTS Playground](https://platform.inworld.ai/tts-playground).

### Low-Latency for Real-Time / Conversational AI

```bash
# Ultra-fast response for chatbots & game NPCs (~120ms)
belt app run inworld/text-to-speech-1-5-mini --input '{
  "text": "Welcome, traveler. What brings you to our village?",
  "voice_id": "Clive",
  "speaking_rate": 0.9
}'
```

## Voice Generation Examples

### Professional Narration

```bash
belt app run infsh/kokoro-tts --input '{
  "prompt": "Welcome to our quarterly earnings call. Today we will discuss the financial performance and strategic initiatives for the past quarter.",
  "voice": "am_michael",
  "speed": 1.0
}'
```

### Conversational Style

```bash
belt app run infsh/dia-tts --input '{
  "text": "Hey, so I was thinking about that project we discussed. What if we tried a different approach?",
  "voice": "conversational"
}'
```

### Audiobook Narration

```bash
belt app run infsh/kokoro-tts --input '{
  "prompt": "Chapter One. The morning mist hung low over the valley as Sarah made her way down the winding path. She had been walking for hours.",
  "voice": "bf_emma",
  "speed": 0.9
}'
```

### Video Voiceover

```bash
belt app run infsh/kokoro-tts --input '{
  "prompt": "Introducing the next generation of productivity. Work smarter, not harder.",
  "voice": "af_nicole",
  "speed": 1.1
}'
```

### Podcast Host

```bash
belt app run infsh/kokoro-tts --input '{
  "prompt": "Welcome back to Tech Talk! Im your host, and today we are diving deep into the world of artificial intelligence.",
  "voice": "am_adam"
}'
```

## Multi-Voice Conversation

```bash
# Generate dialogue between two speakers
# Speaker 1
belt app run infsh/kokoro-tts --input '{
  "prompt": "Have you seen the latest AI developments? Its incredible how fast things are moving.",
  "voice": "am_michael"
}' > speaker1.json

# Speaker 2
belt app run infsh/kokoro-tts --input '{
  "prompt": "I know, right? Just last week I tried that new image generator and was blown away.",
  "voice": "af_sarah"
}' > speaker2.json

# Merge conversation
belt app run infsh/media-merger --input '{
  "audio_files": ["<speaker1-url>", "<speaker2-url>"],
  "crossfade_ms": 300
}'
```

## Long-Form Content

### Chunked Processing

For content over 5000 characters, split into chunks:

```bash
# Process long text in chunks
TEXT="Your very long text here..."

# Split and generate
# Chunk 1
belt app run infsh/kokoro-tts --input '{
  "prompt": "<chunk-1>",
  "voice": "bf_emma"
}' > chunk1.json

# Chunk 2
belt app run infsh/kokoro-tts --input '{
  "prompt": "<chunk-2>",
  "voice": "bf_emma"
}' > chunk2.json

# Merge chunks
belt app run infsh/media-merger --input '{
  "audio_files": ["<chunk1-url>", "<chunk2-url>"],
  "crossfade_ms": 100
}'
```

## Voice + Video Workflow

### Add Voiceover to Video

```bash
# 1. Generate voiceover
belt app run infsh/kokoro-tts --input '{
  "prompt": "This stunning footage shows the beauty of nature in its purest form.",
  "voice": "am_michael"
}' > voiceover.json

# 2. Merge with video
belt app run infsh/media-merger --input '{
  "video_url": "https://your-video.mp4",
  "audio_url": "<voiceover-url>"
}'
```

### Create Talking Head

```bash
# 1. Generate speech
belt app run infsh/kokoro-tts --input '{
  "prompt": "Hi, Im excited to share some updates with you today.",
  "voice": "af_sarah"
}' > speech.json

# 2. Animate with avatar
belt app run bytedance/omnihuman-1-5 --input '{
  "image_url": "https://portrait.jpg",
  "audio_url": "<speech-url>"
}'
```

## Speed and Pacing

| Speed | Effect | Use For |
|-------|--------|---------|
| 0.8 | Slow, deliberate | Audiobooks, meditation |
| 0.9 | Slightly slow | Education, tutorials |
| 1.0 | Normal | General purpose |
| 1.1 | Slightly fast | Commercials, energy |
| 1.2 | Fast | Quick announcements |

```bash
# Slow narration
belt app run infsh/kokoro-tts --input '{
  "prompt": "Take a deep breath. Let yourself relax.",
  "voice": "bf_emma",
  "speed": 0.8
}'
```

## Punctuation for Pacing

Use punctuation to control speech rhythm:

| Punctuation | Effect |
|-------------|--------|
| Period `.` | Full pause |
| Comma `,` | Brief pause |
| `...` | Extended pause |
| `!` | Emphasis |
| `?` | Question intonation |
| `-` | Quick break |

```bash
belt app run infsh/kokoro-tts --input '{
  "prompt": "Wait... Did you hear that? Something is coming. Something big!",
  "voice": "am_adam"
}'
```

## Best Practices

1. **Match voice to content** - Professional voice for business, casual for social
2. **Use punctuation** - Control pacing with periods and commas
3. **Keep sentences short** - Easier to generate and sounds more natural
4. **Test different voices** - Same text sounds different across voices
5. **Adjust speed** - Slightly slower often sounds more natural
6. **Break long content** - Process in chunks for consistency

## Use Cases

- **Voiceovers** - Video narration, commercials
- **Audiobooks** - Full book narration
- **Podcasts** - AI hosts and guests
- **E-learning** - Course narration
- **Accessibility** - Screen reader content
- **IVR** - Phone system messages
- **Content localization** - Translate and voice

## Related Skills

```bash
# ElevenLabs TTS (premium, 22+ voices)
npx skills add inference-sh/skills@elevenlabs-tts

# ElevenLabs voice changer (transform recordings)
npx skills add inference-sh/skills@elevenlabs-voice-changer

# All TTS models
npx skills add inference-sh/skills@text-to-speech

# Podcast creation
npx skills add inference-sh/skills@ai-podcast-creation

# AI avatars
npx skills add inference-sh/skills@ai-avatar-video

# Video generation
npx skills add inference-sh/skills@ai-video-generation

# Full platform skill
npx skills add inference-sh/skills@infsh-cli
```

Browse audio apps: `belt app store --category audio`