1┌────────────┐    ┌─────────────┐    ┌────────────┐
2│   User     │───▶│ Speech-to-  │───▶│   Agent    │
3│   Speech   │    │    Text     │    │  (Process) │
4└────────────┘    └─────────────┘    └────────────┘
5                                            │
6┌────────────┐    ┌─────────────┐           │
7│   Audio    │◀───│ Text-to-    │◀──────────┘
8│   Output   │    │   Speech    │
9└────────────┘    └─────────────┘

11. Speech-to-Text (STT)
2   - Convert voice → text
3   - Also: ASR (Automatic Speech Recognition)
4   - Providers: Whisper, Google, Azure
5 
62. Text-to-Speech (TTS)
7   - Convert text → voice
8   - Natural-sounding voices
9   - Providers: ElevenLabs, Google, Azure
10 
113. Voice Agents
12   - Combine STT + Agent + TTS
13   - Phone systems
14   - Voice assistants

1Pros:
2✅ Highly accurate
3✅ Multi-language
4✅ Free (local) / cheap (API)
5✅ Handles accents well
6 
7Cons:
8❌ Batch only (no streaming)
9❌ Requires audio file
10 
11Use case:
12- Transcription
13- Voice messages
14- Recorded content

1Pros:
2✅ Streaming support
3✅ Real-time transcription
4✅ Many languages
5✅ Good accuracy
6 
7Cons:
8❌ Pay per minute
9❌ Complex setup
10 
11Use case:
12- Live transcription
13- Phone systems
14- Real-time agents

1Pros:
2✅ Enterprise features
3✅ Custom models
4✅ Streaming
5✅ Microsoft integration
6 
7Use case:
8- Enterprise deployments
9- Custom vocabulary
10- High security needs

1Pros:
2✅ Ultra-realistic voices
3✅ Voice cloning
4✅ Emotional range
5✅ Easy to use
6 
7Cons:
8❌ Higher cost
9❌ Character limits
10 
11Best for:
12- High-quality experience
13- Brand voices
14- Content creation

1Pros:
2✅ Many voices/languages
3✅ SSML support
4✅ Neural voices available
5✅ Good free tier
6 
7Best for:
8- Multi-language
9- Cost-effective
10- Simple integration

1Pros:
2✅ Simple API
3✅ Good quality
4✅ Fast generation
5✅ Multiple voices
6 
7Best for:
8- Quick implementation
9- OpenAI ecosystem
10- General use cases

1Voiceflow supports voice natively:
2 
31. Create project
42. Select "Voice Assistant"
53. Build flows (same as chat)
64. Voiceflow handles STT/TTS
75. Deploy to Alexa, Google Assistant

1Workflow:
21. Receive audio file
32. Send to Whisper API → Get text
43. Process with AI
54. Send text to ElevenLabs → Get audio
65. Return audio

1Telegram Bot (Make):
2 
3Trigger: Voice message received
4   ↓
5HTTP: Send audio to Whisper
6   ↓
7Get transcript text
8   ↓
9HTTP: Send to OpenAI (process)
10   ↓
11HTTP: Send response to ElevenLabs
12   ↓
13Action: Send voice reply

11. Sign up at elevenlabs.io
22. Get API key
33. Choose voices:
4   - Pre-made voices
5   - Clone your voice
6   - Generate custom

1Categories:
2- Narrative (storytelling)
3- Conversational (casual)
4- Professional (business)
5- Characters (unique styles)
6 
7Choose based on:
8- Brand personality
9- Use case
10- Audience

1Endpoint: https://api.elevenlabs.io/v1/text-to-speech
2 
3Request:
4{
5  "text": "Hello, how can I help you?",
6  "voice_id": "21m00Tcm4TlvDq8ikWAM",
7  "model_id": "eleven_monolingual_v1"
8}
9 
10Response: Audio file (mp3)

1Endpoint: https://api.openai.com/v1/audio/transcriptions
2 
3Request:
4- Model: whisper-1
5- File: audio file
6- Language: optional
7 
8Response:
9{
10  "text": "Transcribed text here"
11}

1Audio formats:
2- mp3
3- mp4
4- mpeg
5- m4a
6- wav
7- webm
8- Maximum: 25MB

1Sources:
2- Telegram voice message
3- Uploaded file
4- Phone call (Twilio)
5- Web recording

1HTTP Module:
2- URL: OpenAI Whisper endpoint
3- Method: POST
4- Body: Form data with audio file
5- Parse response: Get text

1Send to:
2- OpenAI for response
3- Your AI agent
4- Custom logic
5 
6Get text reply

1HTTP Module:
2- URL: ElevenLabs endpoint
3- Method: POST
4- Body: JSON with text
5- Response: Binary (audio)

1Options:
2- Send audio file
3- Play audio
4- Stream to user

1Control pronunciation:
2- SSML tags
3- Phonetic spelling
4- Custom dictionaries
5 
6Example issues:
7- Names: "Nguyen" → "Win"
8- Numbers: "2023" vs "twenty twenty-three"
9- Acronyms: "API" vs "A-P-I"

1Common issues:
2- No audio detected
3- Poor quality audio
4- Background noise
5- Accent issues
6- Network problems

1Test for:
2- Accuracy of transcription
3- Natural TTS sound
4- Response latency
5- Different accents
6- Background noise
7- Various devices

1- Test with real voice input
2- Record test scenarios
3- Use different devices
4- Test network conditions