Multilingual support agent
Overview
Build a dynamic customer support agent for GlobalTech International that automatically detects and responds in the customer’s language (English, Spanish, or French) during conversation, with seamless language switching and real-time adaptation.
What You’ll Build:
- Assistant with automatic multilingual transcription
- Dynamic voice adaptation for detected languages
- Real-time language switching during conversations
- Phone number setup for seamless international support
- Advanced prompting for cultural context awareness
Alternative Approach: For a more structured multilingual experience with explicit language selection, see our Workflow-based multilingual support that guides customers through language selection and dedicated conversation paths.
Prerequisites
- A Vapi account.
Scenario
We will be creating a dynamic multilingual customer support agent for GlobalTech International, a technology company serving customers across North America, Europe, and Latin America. Unlike structured language selection, this agent automatically detects the customer’s language from their speech and can switch languages mid-conversation, providing a truly seamless multilingual experience.
1. Create a Multilingual Knowledge Base
Upload the files
Dashboard
TypeScript (Server SDK)
Python (Server SDK)
cURL
- Navigate to Files in your Vapi Dashboard
- Click Choose file and upload all three CSV files
- Note the file IDs for use in creating multilingual tools
2. Create a Multilingual Assistant
Dashboard
TypeScript (Server SDK)
Python (Server SDK)
cURL
3. Configure Multilingual Transcription
Set up automatic language detection
Dashboard
TypeScript (Server SDK)
Python (Server SDK)
cURL
- In your assistant configuration, find the Transcriber section
- Provider: Select
Deepgram
(recommended for speed and accuracy) - Model: Choose
Nova 2
orNova 3
- Language: Select
Multi
(enables automatic language detection) - Alternative: Use
Google
provider withMultilingual
language setting
4. Configure Multilingual Voice Synthesis
Set up language-specific voices
Dashboard
TypeScript (Server SDK)
Python (Server SDK)
cURL
- In the Voice section of your assistant:
- Provider: Select
Azure
(best multilingual coverage) - Voice: Choose primary voice
en-US-AriaNeural
(English) - Add fallback voices:
- Spanish:
es-ES-ElviraNeural
(Spain) ores-MX-DaliaNeural
(Mexico) - French:
fr-FR-DeniseNeural
(France) orfr-CA-SylvieNeural
(Canada)
- Spanish:
- Alternative providers: ElevenLabs, OpenAI, or PlayHT all support multiple languages
5. Configure System Prompt
6. Add Multilingual Tools
Dashboard
TypeScript (Server SDK)
Python (Server SDK)
cURL
Create customer lookup tool
-
Click
Create Tool
. -
Select
Function
as your tool type. -
Change tool name to
lookup_customer
. -
Add function description:
Function Description -
Add knowledge base:
- Name:
customers
- Description:
Customer database with multilingual support preferences
- File IDs:
<File ID of your customers.csv file>
- Name:
Create product information tool
-
Click
Create Tool
. -
Select
Function
as your tool type. -
Change tool name to
get_product_info
. -
Add function description:
Function Description -
Add knowledge base:
- Name:
products
- Description:
Product catalog with multilingual descriptions
- File IDs:
<File ID of your products.csv file>
- Name:
Create support articles tool
-
Click
Create Tool
. -
Select
Function
as your tool type. -
Change tool name to
search_support_articles
. -
Add function description:
Function Description -
Add knowledge base:
- Name:
support_articles
- Description:
Multilingual support documentation and troubleshooting guides
- File IDs:
<File ID of your support_articles.csv file>
- Name:
7. Set Up Phone Number
Dashboard
TypeScript (Server SDK)
Python (Server SDK)
cURL
Create a new phone number
- Click
Create Phone Number
. - Choose
Free Vapi Number
to get started. - Select your preferred area code (e.g.,
212
for New York).
Configure the phone number
- Set the
Phone Number Name
toGlobalTech International Support
. - Under
Inbound Settings
, findAssistant
dropdown and selectGlobalTech Support Agent
. - Optional: Configure advanced settings:
- Enable call recording for quality assurance
- Set up voicemail detection
- Configure business hours if needed
- Changes are saved automatically.
Alternative: Workflow-Based Language Selection
For a more structured approach with explicit language selection, see our comprehensive Workflow-based multilingual support guide. This approach lets customers choose their language at the start of the call, then routes them to dedicated conversation paths optimized for each language.
Benefits of workflow approach
- Clearer language selection: Customers explicitly choose their language
- Dedicated language paths: Each language has its own conversation flow
- Optimized voices: Language-specific voices for better quality
- Easier maintenance: Separate prompts and logic for each language
- Better analytics: Track language preferences and usage patterns
Provider Support Summary
Speech-to-Text (Transcription):
- Deepgram: Nova 2, Nova 3 with “Multi” language setting
- Google: Latest models with “Multilingual” language setting
- All other providers: Single language only, no automatic detection
Text-to-Speech (Voice Synthesis):
- Azure: 400+ voices across 140+ languages (recommended for coverage)
- ElevenLabs: 30+ languages with premium quality
- OpenAI: 50+ languages with consistent quality
- PlayHT: 80+ languages, cost-effective
- All providers: Support multiple languages natively
Language Models:
- All major LLMs (GPT-4o, Claude, Gemini, Llama, etc.): Native multilingual support
Next Steps
Just like that, you’ve built a dynamic multilingual customer support agent that automatically detects and responds in the customer’s language with seamless mid-conversation language switching.
Consider reading the following guides to further enhance your multilingual implementation:
- Workflow-based Multilingual Support - Compare with structured language selection approach
- Multilingual Configuration Guide - Learn about all multilingual configuration options
- Custom Tools - Build advanced multilingual tools and integrations