Multilingual

RevRing agents speak and understand 20 languages, plus a multilingual mode for callers who switch languages, with 300+ voices.

Supported Languages

The agent’s language setting chooses how the agent listens and speaks:

Language	Code	Language	Code
English	`en`	Arabic	`ar`
Spanish	`es`	Russian	`ru`
French	`fr`	Polish	`pl`
Chinese	`zh`	Dutch	`nl`
Korean	`ko`	Hindi	`hi-IN`
Japanese	`ja`	Bengali	`bn-IN`
German	`de`	Tamil	`ta-IN`
Italian	`it`	Telugu	`te-IN`
Portuguese	`pt`	Gujarati	`gu-IN`
Multilingual	`multi`	Kannada, Marathi	`kn-IN`, `mr-IN`

Multilingual mode

With "language": "multi" the agent understands callers speaking English, Spanish, French, German, Italian, Portuguese, Dutch, Russian, Hindi or Japanese, including callers who switch mid-call, and replies in the language the caller speaks. Tell the agent how to choose in the prompt, for example: “Reply in the language the caller uses. If they switch to Spanish, continue in Spanish.” Pick a voice that sounds natural in every language you expect. Voices are also available in Turkish, Greek, Ukrainian, Danish, Estonian, Finnish, Norwegian, Swedish and Vietnamese; preview them in the Voice Library.

Voice Flexibility: Any voice can be used with any language setting. For example, you can use a Spanish-labeled voice on an English-language agent to achieve a Spanish accent, or mix and match voices and languages to create the exact speaking style you need.

Setting Agent Language

Via Dashboard

Navigate to Agents and select your agent
Go to the Overview tab
Select your desired Language from the dropdown and click Save
Go to the Voice tab
Choose a Voice that matches your selected language
Click Save Voice

You can preview all available voices in the Voice Library.

Via API

Set the language when creating or updating an agent:

curl -X PATCH https://api.revring.ai/v1/agents/agent_123abc \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "language": "es",
    "voiceId": "revring-rafael"
  }'

Supported language codes:

en (English)
es (Spanish)
pt (Portuguese)
de (German)
it (Italian)
nl (Dutch)
zh (Chinese)
ja (Japanese)
hi (Hindi)
tr (Turkish)
el (Greek)
uk (Ukrainian)
ar (Arabic)
da (Danish)
et (Estonian)
fi (Finnish)
nb (Norwegian Bokmål)
no (Norwegian)
sv (Swedish)
vi (Vietnamese)

One agent, many languages

Use one agent for callers in different languages: set the language per call, and give the agent a voice and opening line for each language.

Language per call

When you know the caller’s language before the call (from your CRM, for example), pass it when you place the call. The agent listens and speaks in that language for this call only:

curl -X POST https://api.revring.ai/v1/calls \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "agentId": "AGENT_ID",
    "toNumber": "+15551234567",
    "fromNumber": "+15559876543",
    "language": "es"
  }'

For inbound calls, your pre-call webhook can answer with "overrides": { "language": "es" } to run that call in Spanish. The {{language}} variable carries the call’s language.

Language presets

languagePresets gives the agent a voice and an opening line per language. When a call runs in a language that has a preset, the agent uses that preset’s voice and opening line instead of its own:

curl -X PATCH https://api.revring.ai/v1/agents/{agentId} \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "languagePresets": {
      "es": { "voiceId": "SPANISH_VOICE_ID", "firstMessage": "Hola {{first_name}}, le habla Maya de Northside." },
      "fr": { "voiceId": "FRENCH_VOICE_ID", "firstMessage": "Bonjour, ici Maya de Northside." }
    }
  }'

A preset can set the voice, the opening line, or both. Whatever it leaves out comes from the agent.
A regional code uses its base language’s preset when it has none of its own: a call in pt-BR uses the pt preset.
A voice or opening line given explicitly for one call (per-call voiceId, or the pre-call webhook’s voiceId or firstMessage) wins over the preset.
Preset voices come from the Voice Library (GET /v1/voices); unknown voices are refused.
Agents imported from ElevenLabs bring their per-language opening lines.

Writing Prompts for Multilingual Agents

Best Practice: Match Prompt Language

For optimal performance, write your agent’s prompt in the same language as the agent’s configured language setting: Spanish Agent Example:

Eres un asistente de servicio al cliente profesional y amigable.

INSTRUCCIONES:
- Saluda a los clientes calurosamente
- Responde preguntas sobre nuestros productos
- Mantén las respuestas concisas y útiles

Siempre sé cortés y profesional.

Cross-Language Prompts

While not required, agents can follow prompts written in a different language than their speaking language. The AI is intelligent enough to understand instructions in one language while conversing in another: English Prompt for Spanish Agent:

You are a customer service agent speaking Spanish.

INSTRUCTIONS:
- Greet customers warmly in Spanish
- Answer questions about our products
- Keep responses under 30 seconds

Always be polite and professional.

However, for best results and consistency, we recommend writing prompts in the agent’s configured language.

Language System Variable

The {{language}} system variable is automatically available in all prompts and contains the agent’s language code:

You are speaking in {{language}}.

Current language: {{language}}
Timezone: {{timezone}}
Current time: {{current_time}}

This can be useful for building flexible prompts or logging purposes.

Voice Selection

Each language has multiple voices to choose from. Visit the Voice Library to preview all available voices in your selected language.

Backup Voice

Every agent can set a Backup Voice (in the dashboard Voice tab, or fallbackVoiceId via the API) for seamless voice continuity. In the rare case a voice is temporarily unavailable, the agent switches to its backup voice instantly and the conversation continues as normal. Leave it on Automatic to let the platform manage this for you. For multilingual agents we recommend choosing a backup voice in the agent’s own language.

English Voice Categories

English offers two categories of voices:

English Ultra-Realistic (Beta): Cutting-edge voices with exceptional naturalness and expressiveness
English Stable: Reliable, production-ready voices with consistent performance

If you experience instability with Ultra-Realistic voices, try switching to an English Stable voice for better reliability.

Troubleshooting

Voice Instability

If you notice inconsistent voice quality or unexpected behavior:

Switch Voice Category: For English agents, try switching from Ultra-Realistic to Stable voices
Verify Language Match: Ensure the selected voice matches your agent’s language setting

Need Help?

For assistance with multilingual setup, voice selection, or configuration, contact support. Our team can help you:

Choose the right voices for your use case
Optimize prompts for specific languages
Configure multilingual routing strategies
Troubleshoot voice quality issues

Complete Example

Here’s a complete Spanish agent configuration: Via API:

curl -X POST https://api.revring.ai/v1/agents \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "sipTrunkId": "trunk_abc123",
    "name": "Asistente en Español",
    "language": "es",
    "voiceId": "revring-rafael",
    "promptTemplate": "Eres un asistente de servicio al cliente. Ayuda al cliente con sus preguntas.",
    "firstMessage": "Hola, bienvenido. ¿Cómo puedo ayudarte hoy?"
  }'

Via Dashboard:

Create agent with name “Asistente en Español”
In Overview tab:
- Language: Spanish
- First Message: “Hola, bienvenido. ¿Cómo puedo ayudarte hoy?”
- Prompt: “Eres un asistente de servicio al cliente. Ayuda al cliente con sus preguntas.”
In Voice tab:
- Voice: Rafael

For callers who switch languages mid-call, use multilingual mode. For a market that speaks one language, a dedicated agent in that language with a native voice gives the best quality.

Getting started

Platform

Supported Languages

Multilingual mode

Setting Agent Language

Via Dashboard

Via API

One agent, many languages

Language per call

Language presets

Writing Prompts for Multilingual Agents

Best Practice: Match Prompt Language

Cross-Language Prompts

Language System Variable

Voice Selection

Backup Voice

English Voice Categories

Troubleshooting

Voice Instability

Need Help?

Complete Example

​Supported Languages

​Multilingual mode

​Setting Agent Language

​Via Dashboard

​Via API

​One agent, many languages

​Language per call

​Language presets

​Writing Prompts for Multilingual Agents

​Best Practice: Match Prompt Language

​Cross-Language Prompts

​Language System Variable

​Voice Selection

​Backup Voice

​English Voice Categories

​Troubleshooting

​Voice Instability

​Need Help?

​Complete Example

Supported Languages

Multilingual mode

Setting Agent Language

Via Dashboard

Via API

One agent, many languages

Language per call

Language presets

Writing Prompts for Multilingual Agents

Best Practice: Match Prompt Language

Cross-Language Prompts

Language System Variable

Voice Selection

Backup Voice

English Voice Categories

Troubleshooting

Voice Instability

Need Help?

Complete Example