# Hindi Voice Agents

> Complete guide to building production Hindi voice agents with optimal STT, TTS, and LLM configurations.

Source: https://edesy.in/docs/voice-agent/languages/hindi

Hindi (hi-IN) has excellent support across all major providers, making it ideal for voice agents serving the Indian market.

## Quick Start

```json
{
  "agent": {
    "name": "Hindi Support Agent",
    "language": "hi-IN",

    "llmProvider": "gemini-2.5",
    "llmModel": "gemini-2.5-flash-lite",

    "sttProvider": "deepgram",
    "sttModel": "nova-3",

    "ttsProvider": "azure",
    "ttsVoice": "hi-IN-SwaraNeural",

    "greetingMessage": "नमस्ते! मैं आपकी कैसे मदद कर सकता हूँ?",

    "prompt": "आप एक मददगार ग्राहक सेवा एजेंट हैं। हिंदी में जवाब दें।"
  }
}
```

## Provider Options

### STT (Speech-to-Text)

| Provider | Model | WER | Latency | Cost/min |
|----------|-------|-----|---------|----------|
| **Deepgram** | nova-3 | 8-12% | ~150ms | ₹0.35 |
| Google | chirp_2 | 10-14% | ~200ms | ₹1.34 |
| ElevenLabs | scribe | 12-15% | ~180ms | ₹0.56 |
| Azure | speech | 12-16% | ~220ms | ₹0.84 |

**Recommendation**: Deepgram Nova-3 for best accuracy and lowest cost.

### TTS (Text-to-Speech)

| Provider | Voices | Quality | Cost/min |
|----------|--------|---------|----------|
| **Azure** | 4 Neural | Excellent | ₹1.01 |
| Google | 2 Neural | Good | ₹1.34 |
| ElevenLabs | Multilingual | Good | ₹12.60 |

**Recommendation**: Azure Neural voices for best quality Hindi speech.

### LLM

| Provider | Model | Hindi Understanding | Cost/min |
|----------|-------|---------------------|----------|
| **Gemini 2.5** | flash-lite | Excellent | ₹0.04 |
| Gemini 2.0 | flash | Excellent | ₹0.05 |
| GPT-4o | mini | Good | ₹0.08 |

**Recommendation**: Gemini 2.5 Flash-Lite for best Hindi understanding at lowest cost.

## Azure Hindi Voices

| Voice | Gender | Style | Best For |
|-------|--------|-------|----------|
| `hi-IN-SwaraNeural` | Female | Professional, warm | Customer support |
| `hi-IN-MadhurNeural` | Male | Professional | Business calls |
| `hi-IN-AnanyaNeural` | Female | Conversational | Casual interactions |
| `hi-IN-ArjunNeural` | Male | Young, friendly | Youth-focused apps |

### Voice Configuration

```json
{
  "ttsProvider": "azure",
  "ttsVoice": "hi-IN-SwaraNeural",
  "ttsConfig": {
    "speakingRate": 1.0,
    "pitch": "0%"
  }
}
```

## Hinglish (Hindi-English Mix)

For agents that handle code-switching between Hindi and English:

```json
{
  "agent": {
    "name": "Hinglish Agent",
    "language": "hi-IN",

    "sttProvider": "deepgram",
    "sttConfig": {
      "language": "hi",
      "model": "nova-3"
    },

    "prompt": "You are a customer support agent. Respond in Hinglish (Hindi-English mix) as commonly spoken in urban India. Example: 'Aapka order ship ho gaya hai, delivery Friday tak expected hai.'"
  }
}
```

### Hinglish Prompt Tips

```
## Language Guidelines
- Mix Hindi and English naturally as spoken in urban India
- Use English for technical terms: order, delivery, payment, refund
- Use Hindi for greetings and emotional expressions
- Match the customer's language style

## Examples
Good: "Aapka order successfully place ho gaya hai"
Good: "Main abhi check karta hoon aapka status"
Avoid: Pure formal Hindi that sounds unnatural
```

## Devanagari Script Handling

### Prompt in Hindi

```json
{
  "prompt": "आप एक सहायक एजेंट हैं। कृपया ग्राहकों की मदद करें।\n\n## नियम\n- विनम्र रहें\n- स्पष्ट उत्तर दें\n- समस्याओं का समाधान करें"
}
```

### Transliteration Support

Users may type in Roman script:

```json
{
  "prompt": "Users may write Hindi in Roman script (e.g., 'mujhe order status chahiye'). Understand both Devanagari (हिंदी) and Roman transliterations. Always respond in Devanagari script unless the user prefers Roman."
}
```

## Honorifics & Formality

Hindi has formal (आप) and informal (तुम) address:

```json
{
  "prompt": "## Formality Guidelines\n- Always use 'आप' (respectful you) not 'तुम'\n- Add 'जी' suffix for respect: 'हाँ जी', 'नहीं जी'\n- Use formal greetings: 'नमस्ते', 'नमस्कार'\n- Avoid overly casual language"
}
```

### Formal vs Informal

| Formal (Business) | Informal (Casual) |
|-------------------|-------------------|
| आप कैसे हैं? | तुम कैसे हो? |
| कृपया बताएं | बताओ ना |
| धन्यवाद | थैंक्स |
| जी, बिल्कुल | हाँ हाँ |

## Number Handling

Hindi uses the Indian numbering system:

```json
{
  "prompt": "When speaking numbers, use Indian format:\n- 1,00,000 = एक लाख (not one hundred thousand)\n- 10,00,000 = दस लाख\n- 1,00,00,000 = एक करोड़\n\nSpell out amounts clearly: '₹1,50,000' as 'एक लाख पचास हज़ार रुपये'"
}
```

## Regional Considerations

### Common Hindi Variants

| Region | Characteristics | Notes |
|--------|----------------|-------|
| Standard Hindi | Neutral accent | Best for pan-India |
| Delhi Hindi | Urban, English-mixed | Common in North |
| Mumbai Hindi | Marathi influence | Common in West |
| Bihari Hindi | Regional vocabulary | Eastern India |

### Greeting by Time

```go
func getHindiGreeting(hour int) string {
    switch {
    case hour < 12:
        return "सुप्रभात" // Good morning
    case hour < 17:
        return "नमस्कार" // Good afternoon
    default:
        return "शुभ संध्या" // Good evening
    }
}
```

## Complete Example

### Customer Support Agent

```json
{
  "agent": {
    "name": "Hindi Customer Support",
    "language": "hi-IN",

    "llmProvider": "gemini-2.5",
    "llmModel": "gemini-2.5-flash-lite",
    "llmTemperature": 0.7,

    "sttProvider": "deepgram",
    "sttModel": "nova-3",
    "sttConfig": {
      "language": "hi",
      "keywords": ["ऑर्डर:2", "रिफंड:2", "डिलीवरी:2"]
    },

    "ttsProvider": "azure",
    "ttsVoice": "hi-IN-SwaraNeural",

    "greetingMessage": "नमस्ते! मैं आपकी सहायता के लिए हाज़िर हूँ। आप अपने ऑर्डर के बारे में पूछ सकते हैं, या किसी और विषय पर मदद ले सकते हैं।",

    "prompt": "आप एक ग्राहक सहायता एजेंट हैं।\n\n## आपकी भूमिका\n- ग्राहकों की समस्याओं का समाधान करें\n- विनम्र और सहायक रहें\n- स्पष्ट और संक्षिप्त उत्तर दें\n\n## भाषा\n- शुद्ध हिंदी या Hinglish दोनों चलेगी\n- ग्राहक की भाषा शैली को मैच करें\n- 'आप' का प्रयोग करें, 'तुम' नहीं",

    "allowInterruptions": true
  }
}
```

## Testing Hindi Agents

### Test Phrases

```
# Greetings
"नमस्ते"
"हैलो"

# Order queries
"मेरा ऑर्डर कहाँ है?"
"मुझे ऑर्डर स्टेटस चाहिए"
"order number 12345"

# Hinglish
"Mujhe refund chahiye"
"Order kab aayega?"

# Edge cases
"हाँ जी" (short affirmative)
"नहीं नहीं" (repetition)
```

### Common STT Errors

| Spoken | Misheard As | Solution |
|--------|-------------|----------|
| हाँ | हा, हां | Add keyword boost |
| नहीं | नई, नहि | Post-processing |
| ऑर्डर | आर्डर | Custom vocabulary |

## Cost Optimization

### Budget Configuration

```json
{
  "sttProvider": "deepgram",
  "ttsProvider": "google",
  "llmProvider": "gemini-2.5"
}
```

**Estimated cost**: ₹0.44/minute

### Quality Configuration

```json
{
  "sttProvider": "google",
  "sttModel": "chirp_2",
  "ttsProvider": "azure",
  "llmProvider": "gemini"
}
```

**Estimated cost**: ₹2.40/minute

## Next Steps

- [Tamil](https://edesy.in/docs/voice-agent/languages/tamil) - Tamil configuration
- [Indian Languages](https://edesy.in/docs/voice-agent/languages/indian-languages) - All Indian languages
- [Function Calling](https://edesy.in/docs/voice-agent/features/function-calling) - Add tools