Voice to Text Hinglish: How to Build Multilingual Agents

Bolti, a voice AI platform for phone agents, enables you to build and run production-ready conversational agents that handle real-time voice calls with sub-second latency. For businesses operating in India, handling the natural mix of Hindi and English—commonly known as Hinglish—is essential. With Bolti, you can build agents that process Hinglish speech-to-text (STT) natively, ensuring that your callers are understood exactly as they speak, with pricing starting at just ₹6/min pay-as-you-go.

Whether you are building outbound sales bots, customer support desks, or automated appointment schedulers, handling voice to text Hinglish requires deep integration between low-latency speech recognition and flexible LLM comprehension. Bolti handles this pipeline seamlessly so you do not have to stitch together multiple API providers yourself.

What is voice to text Hinglish on phone calls?

Voice to text Hinglish refers to the real-time transcription and comprehension of spoken Hindi mixed with English vocabulary during voice calls. In India, most callers do not speak pure Hindi or pure English; instead, they naturally switch between the two languages within a single sentence.

For example, a customer might say, "Mera order deliver kab hoga? Tracking link send kar do."

To handle this call effectively in 2026, a voice agent needs:

1. Telephony-grade speech recognition: Fast, noise-tolerant transcription that captures both Hindi and English words accurately.
2. Contextual LLM understanding: A language model that understands colloquial phrasing, intent, and mixed-language syntax.
3. Low-latency execution: The entire loop of transcription, LLM processing, and text-to-speech (TTS) must happen in under a second to maintain a natural conversation flow.

By utilizing Bolti's native multilingual support, you can deploy agents that handle these complex voice patterns without frustrating pauses or misunderstandings.

How to set up a Hinglish voice agent in Bolti

Setting up a voice agent that understands Hinglish takes less than 10 minutes. Because Bolti integrates the entire telephony, STT, LLM, and TTS stack into a single platform, you do not need to manage complex audio pipelines.

Step 1: Create your agent

Log in to the Bolti dashboard and create a new agent. You can configure the system prompt to instruct the agent to respond in natural Hinglish or pure Hindi/English depending on your business requirements. For instance, you can write: "You are a helpful customer support agent for an e-commerce brand in India. Speak in a friendly, conversational Hinglish tone."

Step 2: Choose a natural voice

Navigate to the Voice tab in your agent settings. Bolti supports multiple TTS providers and displays a curated grid of voice cards.

• You can filter by language (such as Hindi or English) and gender.
• Click the ▶ play button on any voice card (like Anushka or other Hindi/multilingual models) to stream a 3-second preview from the actual provider.
• Choose a voice that sounds natural when speaking mixed-language phrases.

Step 3: Configure your phone number or SIP trunk

To make or receive calls, you can either use Bolti's built-in numbers or bring your own carrier (BYOC) by hooking up your existing SIP trunk (such as Twilio, Plivo, or Exotel). This flexibility ensures you keep your existing business numbers while upgrading to voice AI.

Connecting Hinglish voice inputs to your business APIs

Speech-to-text transcription is only useful if your agent can act on what the customer says. Through Bolti's tool calling system, your agent can convert Hinglish spoken requests into structured API calls to your backend database.

When a customer says, "Mera order cancel kar do, order ID hai 4529," the system processes the request through a simple pipeline:

• STT processing: Bolti converts the audio into text ("Mera order cancel kar do, order ID hai 4529").
• Tool execution: The LLM identifies the intent and triggers a defined Workspace HTTP Tool like cancel_order with the argument order_id=4529.
• API call: Bolti sends a secure HTTP POST request to your endpoint URL (e.g., https://api.yourdomain.com/orders/cancel).
• Response: Your system returns a success response, and the agent verbally confirms in Hinglish: "Aapka order cancel ho gaya hai. Refund process ho chuka hai."

You can easily build and test these integrations directly from the Tools section in the Bolti dashboard, setting up authorization headers (like Bearer tokens or API keys) and request bodies without writing complex middleware code.

Why developers use Bolti's MCP server for agent iteration

If you are a developer building conversational applications, you do not have to spend all your time clicking around a dashboard. Bolti ships with an official Model Context Protocol (MCP) server that exposes your agents, tools, phone numbers, and call logs directly to your local development environment.

By connecting the Bolti MCP server to tools like Cursor or Claude Desktop, you can control your entire voice stack using natural language commands inside your editor:

• "Show me the last 10 call transcripts where the caller spoke in Hinglish."
• "Create a new workspace tool called lookup_customer pointing to our API and assign it to the support agent."
• "Update the system prompt of the sales agent to make the Hinglish greeting warmer."

This workflow allows you to iterate on your voice to text Hinglish prompts, test tool calling, and analyze conversation flows directly from your coding workspace, significantly speeding up deployment.

Set up your first Hinglish voice agent

Ready to see how accurately Bolti handles real-time voice to text Hinglish on a live phone call? You can spin up your first multilingual voice agent in less than 10 minutes and experience telephony-grade performance firsthand.

Sign up today to get 50 free minutes of call time to test your prompts, configure custom tools, and connect your own numbers. No credit card is required to start, and when you are ready to scale, our transparent pricing model keeps your operational costs predictable at just ₹6/minute.

Frequently Asked Questions

How does Bolti handle mixed Hindi and English (Hinglish) inputs?

Bolti uses advanced telephony-grade speech-to-text models that are optimized for multilingual and code-switched languages. The transcribed text is then processed by LLMs configured to understand colloquial Indian phrasing, allowing the agent to follow instructions and call backend tools accurately.

Can the agent reply in Hinglish as well?

Yes. By defining your agent's system prompt to use a conversational Hinglish style, the agent will naturally blend Hindi and English words in its spoken responses. You can choose from a variety of high-quality multilingual voices in the Voice tab to ensure the output sounds natural.

What is the latency for Hinglish voice calls on Bolti?

Bolti is built for production phone calls with sub-second turn-taking latency. Even when performing complex tasks like speech-to-text transcription, LLM processing, tool calling, and text-to-speech synthesis, the agent responds without unnatural pauses.

Can I connect my existing Indian phone numbers?

Yes. Bolti supports Bring Your Own Carrier (BYOC). You can easily connect your existing SIP trunks from providers like Exotel, Plivo, or Twilio to route calls through your Bolti AI agents.