Speech To Text Hinglish: How to Build Multilingual Voice AI

Bolti, a voice AI platform for phone agents, provides native support for speech to text Hinglish, allowing your automated callers to understand the natural blend of Hindi and English spoken across India. With a 50-minute free trial and pay-as-you-go pricing at just ₹6/minute, you can deploy conversational agents that handle real-time interruptions, filter out background noise, and process mixed-language inputs instantly.

For businesses operating in India, building a voice agent that only understands formal Hindi or textbook English is a recipe for high drop-off rates. In practice, callers use Hinglish—mixing vocabulary, grammar, and slang from both languages in a single sentence. Building an agent that can transcribe and comprehend this mix is essential for customer support, outbound sales, and automated operations.

What is speech to text Hinglish and why does it matter?

Speech to text Hinglish is the technology that converts spoken Hinglish—a fluid blend of Hindi and English—into structured, readable text in real-time. Because most standard transcription models are trained strictly on single languages, they fail when a caller says, "Mera order cancel kar do" or "Payment status check karke batao."

If your voice agent cannot resolve these mixed-language phrases, the conversation breaks down. Bolti solves this by utilizing advanced multilingual models optimized for Indian speech patterns. It processes the audio stream, outputs clean text, and feeds it directly into your LLM with sub-second turn-taking latency.

Using a dedicated Hinglish-capable pipeline offers major operational benefits:

• Higher First-Call Resolution: Callers do not have to adapt their natural speech patterns to accommodate a rigid robotic system.
• Accurate Intent Detection: Your backend systems receive clean transcriptions, making it easier for the AI to trigger the right tools.
• Lower Customer Friction: Reduced misunderstandings mean fewer frustrated customers asking to be transferred to a human agent.

How does Bolti process Hinglish on phone calls?

Bolti handles speech to text Hinglish by combining telephony-grade noise cancellation, high-accuracy acoustic models, and LLMs trained on conversational Indian contexts. When a customer speaks, the audio is captured, cleaned of background noise, transcribed, and processed through your configured agent prompt.

Here is how a typical interaction flows through the system:

1. Audio Capture: The caller speaks over a standard telephone line or SIP trunk. Bolti cleans the audio using specialized telephony-grade noise filters.
2. Transcription: The speech to text engine translates the mixed audio stream into text (e.g., "Mujhe apna appointment reschedule karna hai").
3. Tool Triggering (Optional): If the caller's intent requires an action, the LLM triggers a tool. For instance, it might call your API to change a booking time.
4. Natural Response: The agent responds naturally in the same linguistic style or in the language specified in your system prompt.

This pipeline is highly customizable. You can configure your agent's system prompt to instruct it to reply in pure Hindi, clear English, or matching Hinglish, depending on your brand's voice guidelines.

Step-by-step: Setting up a Hinglish voice agent

Setting up an agent capable of processing speech to text Hinglish takes less than ten minutes. You do not need complex programming skills to get started; you can configure the entire flow directly from the Bolti dashboard.

1. Create your agent and set the language

Log in to the Bolti dashboard and create a new agent. In the agent configuration settings, select your primary language. Bolti supports over 80 global languages, including Hindi, Marathi, Tamil, Telugu, Bengali, Gujarati, and English. For a Hinglish setup, select Hindi or English as the base, and use the system prompt to guide the multilingual behavior.

2. Write a clear system prompt

Your system prompt tells the LLM how to behave when it receives the transcribed Hinglish text. A good prompt explicitly gives the agent permission to understand and respond to mixed-language inputs. For example:

"You are a helpful customer support agent for an e-commerce company in India. You will receive inputs in a mix of Hindi and English (Hinglish). Understand the context perfectly. Respond in a friendly, professional Hinglish tone using Latin script (e.g., 'Sure, main aapka order check kar leta hoon')."

3. Connect backend tools to take action

To turn your conversation into action, you can connect your APIs. Bolti supports Workspace HTTP Tools, which allow your agent to interact with your databases, CRMs, or booking systems.

When a caller says, "Mera order status track karo," the LLM recognizes the intent from the Hinglish transcription and invokes the tool. You define these in the Tools tab in your dashboard by setting the name, description, request method, and endpoint URL.

For example, you can build a tool called track_order pointing to https://api.yourdomain.com/orders/track. When the agent decides to run it, Bolti sends a secure HTTP request and passes the output back to the LLM to speak the answer to the caller.

Connecting your own phone numbers

Once your Hinglish agent is configured, you need to connect it to the phone network so customers can call it. Bolti offers a flexible Bring Your Own Carrier (BYOC) model.

You can connect your existing SIP trunks from providers like Twilio, Plivo, or Exotel directly to Bolti. Alternatively, you can purchase and configure virtual phone numbers directly within the platform. If you want to automate your setup programmatically, you can use the Bolti MCP Server in your developer environment to list available phone numbers, assign them to agents, and manage inbound or outbound SIP trunks directly from your editor.

Why businesses choose Bolti for Indian voice AI

Indian businesses face unique challenges when deploying voice automation, from noisy street environments to mixed-language dialects. Bolti is built from the ground up to handle these realities.

• Sub-Second Latency: Phone conversations require instant turn-taking. Bolti's pipeline features real interruption handling, meaning if a caller cuts in while the agent is speaking, the agent stops immediately and listens.
• Telephony-Grade Noise Cancellation: Whether your customer is calling from a busy market in Mumbai or a moving auto-rickshaw, Bolti filters out background noise to ensure high-accuracy transcription.
• Comprehensive Developer Tooling: Every action you can perform in the dashboard is backed by an open REST API. Developers can use the native MCP server for Cursor or Claude Desktop to configure agents, manage tools, and inspect call logs without leaving their code editor.
• Enterprise-Grade Security: Bolti supports on-premises deployment, sub-accounts for white-labeling, runtime PII redaction, and SSO via OIDC/SAML. Our contracts are fully aligned with DPDP, GDPR, and HIPAA compliance standards.

To see how these capabilities perform in real-world scenarios, browse our Bolti use cases to see how other companies deploy automated voice agents for support, collections, and sales.

Set up your first Hinglish voice agent

Ready to build a voice agent that understands your customers exactly how they speak? You can spin up a fully functioning multilingual agent in under 10 minutes.

Sign up for a free trial on the Bolti platform to get 50 free minutes of call time. Once you are ready to scale, our transparent Bolti pricing model keeps costs predictable at just ₹6/minute pay-as-you-go, with no hidden setup fees or complex contracts.

Frequently Asked Questions

Does Bolti support other Indian regional languages?

Yes. Beyond speech to text Hinglish, Bolti natively supports Hindi, Marathi, Tamil, Telugu, Bengali, Gujarati, and English, along with over 80 global languages and regional dialects.

Can the voice agent reply in Hinglish, or does it only understand it?

The agent can do both. By configuring your system prompt, you can instruct the LLM to respond in natural Hinglish (using Latin script), pure Hindi, or clear English depending on your target audience.

How much does it cost to use Bolti for phone calls?

Bolti uses a transparent pay-as-you-go pricing model of ₹6 per minute. New signups receive 50 free minutes to test the platform, build agents, and run test calls.

Can I connect my existing Indian phone numbers to Bolti?

Yes. Bolti supports Bring Your Own Carrier (BYOC), allowing you to connect your existing SIP trunks from providers like Exotel, Tata Tele, Twilio, or Plivo directly to your voice agents.