Install the belt CLI skill:
npx skills add belt-sh/cli
AI Voice Generation
Generate natural AI voices via inference.sh CLI.
Quick Start
Requires inference.sh CLI (
belt). Install instructions
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:
# 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.
Low-Latency for Real-Time / Conversational AI
# 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
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
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
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
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
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
# 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:
# 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
# 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
# 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 |
# 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 |
belt app run infsh/kokoro-tts --input '{
"prompt": "Wait... Did you hear that? Something is coming. Something big!",
"voice": "am_adam"
}'
Best Practices
- Match voice to content - Professional voice for business, casual for social
- Use punctuation - Control pacing with periods and commas
- Keep sentences short - Easier to generate and sounds more natural
- Test different voices - Same text sounds different across voices
- Adjust speed - Slightly slower often sounds more natural
- 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
# 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 list --category audio