Hinglish Speech-to-Text API: Setup Guide for Voice AI (2026)

A hinglish speech to text api is a speech recognition system designed to transcribe mixed Hindi and English speech spoken in natural Indian accents. Bolti, a voice AI platform for phone agents, provides native support for this code-switching with sub-second latency, starting with a 50-minute free trial or ₹6/minute pay-as-you-go pricing.

If you are building voice agents for the Indian market, you cannot rely on standard single-language models. Your callers in cities like Mumbai, Delhi, and Bengaluru will naturally speak Hinglish—a fluid blend of Hindi and English. Handling this requires a robust hinglish speech to text api strategy that can process rapid language switches without dropping calls or losing context.

What is a hinglish speech to text api and why do you need it?

A hinglish speech to text api transcribes mixed Hindi and English speech, allowing voice agents to understand natural Indian conversations. Standard single-language models fail because Indian callers naturally blend both languages (code-switching) during everyday phone calls, leading to broken customer experiences.

While platforms like Bolna AI and Ringg AI also target voice automation, Bolti provides telephony-grade noise cancellation and sub-second turn-taking optimized for real-world Indian phone calls. In India, people rarely stick to one language on a phone call. A customer checking their order status might say:

• "Mera order deliver kab hoga?" (When will my order be delivered?)
• "Mujhe refund chahiye because product damaged tha." (I want a refund because the product was damaged.)
• "Billing address change karna hai, please help." (I need to change my billing address, please help.)

If your voice agent uses a strict English-only or Hindi-only speech-to-text engine, it will misinterpret these blended phrases. The result is a frustrated customer and a failed call. Bolti solves this by integrating advanced, multilingual speech recognition that natively understands Hinglish, Marathi-English, Tamil-English, and over 80 other global languages.

How to configure Hinglish speech-to-text on phone calls

You can configure Hinglish speech-to-text on Bolti in under ten minutes using the dashboard's Agent Settings or the REST API. No complex machine learning code is required.

Step 1: Select your multilingual engine

When creating your agent in the Bolti dashboard, navigate to the Agent Settings. Under the Languages section, select the multilingual model that supports Indian English and Hindi dialect blending. This ensures the speech-to-text engine expects code-switching and transcribes both scripts accurately into a unified text format.

Step 2: Write your system prompt to accept Hinglish

The LLM powering your voice agent needs to understand how to respond to Hinglish. If your system prompt forces the LLM to reply only in formal English, the conversation will feel robotic. Use a prompt like this to align the LLM's behavior:

"You are a helpful customer support assistant for an Indian e-commerce company. The user will speak to you in a mix of Hindi and English (Hinglish). Respond in a natural, conversational Hinglish style using Latin script (e.g., write 'shipped ho gaya hai' instead of 'यह भेज दिया गया है' or 'it has been shipped'). Keep your sentences short and direct."

Step 3: Connect your backend APIs

Once the hinglish speech to text api transcribes the caller's intent, your agent needs to take action. This is where Bolti's tool calling comes into play. A voice agent with tools is an employee—it can query databases, update CRM records, or process refunds in real time.

How do Workspace HTTP Tools process Hinglish voice commands?

Workspace HTTP Tools allow your Hinglish-enabled voice agent to take real-time actions, like checking order statuses or booking appointments, by sending HTTP requests directly to your backend APIs.

You build the tool once in the Tools page of the dashboard, then assign it to whichever agents in that workspace should be able to call it. This means the same lookup_customer tool can be available to your support, sales, and renewals agents without duplicating its definition.

To connect your database:

1. Go to Dashboard → Tools in the left navigation.
2. Click New Tool to open the editor.
3. Set your Tool Name using snake_case (e.g., check_order_status) and write a clear description. The LLM uses this description to decide when to call the tool.
4. Input your Endpoint URL and select your Request Method (like POST or GET).
5. Set up authentication using the typed picker. Bolti supports Bearer Token, Basic Auth, and API Key Header configurations.
6. Save and assign the tool to your Hinglish agent.

During a live Hinglish call, if the user says, "Mera order status check karo," the STT engine transcribes the Hinglish text, the LLM recognizes the intent, and immediately triggers your check_order_status API.

Can you manage Hinglish voice agents using the Bolti MCP Server?

Yes, you can manage your Hinglish voice agents, tools, and phone numbers directly from your code editor using the Bolti Model Context Protocol (MCP) server.

If you prefer working in your code editor rather than clicking through dashboards, Bolti provides a native MCP server that exposes agents, tools, phone numbers, and conversations as tools that an LLM in your editor can call directly. Hooked up to Cursor or Claude Desktop, you can manage your Hinglish-enabled voice agents directly from your terminal or chat interface. You can instruct your editor to:

• "List all active agents and show their configured languages."
• "Create a new tool called verify_pincode and assign it to my Hinglish delivery agent."
• "Pull the transcript of the last Hinglish support call that lasted more than 3 minutes to check STT accuracy."

This workflow allows developers to rapidly iterate on prompt engineering and tool definitions without leaving their development environment.

Key challenges in Hinglish speech recognition (and how to solve them)

The main challenges in Hinglish speech recognition are acoustic background noise, script confusion, and regional accent variations. Bolti resolves these with telephony-grade noise cancellation and models trained on diverse Indian telephonic datasets.

• Acoustic Noise: Many calls in India are made from noisy streets, markets, or moving vehicles. Bolti uses telephony-grade noise cancellation to isolate the speaker's voice before processing it through the STT engine.
• Script Confusion: Some engines try to output Devanagari script for Hindi words and Latin script for English words in the same sentence. Bolti's recommended multilingual configurations output a clean, unified Latin-script transcription, making it easy for the LLM to process.
• Accent Variations: India has diverse regional accents that affect how both English and Hindi words are pronounced. Our speech models are trained on diverse Indian telephonic datasets, ensuring high accuracy across regional accents.

How does Bolti protect sensitive data during Hinglish calls?

Bolti protects sensitive data by encrypting call audio in transit, storing recordings in private object storage accessible only via signed URLs, and offering runtime PII redaction.

Handling customer calls in India means complying with local regulations like the Digital Personal Data Protection (DPDP) Act. Voice agents process highly sensitive information, such as phone numbers, addresses, and payment details. Bolti is built with strict security controls:

• Recordings and transcripts: All call recordings live in private, encrypted object storage, accessible only via time-limited signed URL. Transcripts and call records are workspace-scoped.
• In-flight calls: The realtime audio path is encrypted end-to-end between the realtime audio service, the SIP carrier, and the agent runtime.
• PII Redaction: For enterprise customers with strict compliance needs, Bolti offers PII redaction at runtime, ensuring sensitive data is masked before it ever reaches third-party LLM providers. You can learn more about our enterprise options by visiting our contact page.

Set up your first Hinglish voice agent

Spin up your first Hinglish-enabled voice agent in under 10 minutes. With Bolti, you get pricing details starting at ₹6/minute pay-as-you-go, and your first 50 minutes are completely free.

Sign up for a free trial today to build production-ready voice agents that handle real-time interruptions, process complex tool calls, and speak natural Hinglish.

Frequently Asked Questions

What is a Hinglish speech-to-text API?

A Hinglish speech-to-text API is a speech recognition system trained to transcribe mixed Hindi and English speech spoken in natural Indian accents, preventing transcription errors during code-switching.

How does Bolti handle code-switching in Hinglish?

Bolti utilizes advanced multilingual speech models trained on diverse Indian telephonic datasets. These models natively recognize rapid transitions between Hindi and English within the same sentence, outputting a clean, unified Latin-script transcription.

Can I connect my own database to a Hinglish voice agent?

Yes. Using Bolti's Workspace HTTP Tools, you can connect your backend APIs (such as order tracking or CRM databases) to your voice agent. When a user speaks a Hinglish command, the agent triggers the tool and feeds the API response back to the LLM.

Is Bolti compliant with Indian data protection laws?

Yes. Bolti is built to align with the Digital Personal Data Protection (DPDP) Act. We secure call recordings in private, encrypted object storage, isolate active call sessions, and offer runtime PII redaction to mask sensitive data before it reaches third-party LLM providers.