Voice AI Agents for Indian Languages: Coverage, Setup and Testing

Most callers in India would rather speak their own language than press keys or switch to English. Voice AI agents for Indian languages make that possible: an AI agent that listens in Hindi, Tamil, Malayalam, Telugu, Bengali or Marathi, understands mixed speech like Hinglish, and replies in a natural voice in the same language. This guide is the hub for everything language-related on our blog. It covers which languages are realistic today, how each part of the agent handles them, how to choose the language on each call, and how to test before you go live.

If you are new to the topic, start with our pillar guide on what an AI voice agent is and how it works, then come back here for the language details.

Why language support is harder than it looks

A vendor saying “we support 10 Indian languages” tells you little. A voice agent has three separate parts, and each must handle the language well on real phone calls:

1. Speech to text (STT) must recognise the caller’s words on narrowband 8 kHz phone audio, with background noise, regional accents and English words mixed in.
2. The LLM (the brain) must understand the transcript and write a reply in the right language, script and tone, short enough to be spoken.
3. Text to speech (TTS) must pronounce that reply naturally, including numbers, dates, rupee amounts and names.

If any one of these is weak in a language, the whole conversation fails. A great Malayalam voice is useless if the recogniser mishears the caller, and perfect recognition does not help if the voice reads “₹1,250” as English digits. That is why you should judge language support per component, not per platform.

Which Indian languages matter for voice agents

India has 22 languages in the Eighth Schedule of the Constitution, but call volume is concentrated. In the 2011 Census, Hindi was the mother tongue of 43.63% of the population, followed by Bengali (8.03%), Marathi (6.86%), Telugu (6.70%) and Tamil (5.70%) (Census 2011 figures, compiled on Wikipedia). For a business, though, the right languages are the ones your callers use, which depends on your region far more than on national totals. A Kochi hospital needs Malayalam first; a Chennai lender needs Tamil and English; a national e-commerce brand may need six languages.

Language coverage: what VEXYL and its providers support

The table below shows the large languages with their Census 2011 mother-tongue share, and which speech components cover them in the VEXYL stack: the open-source, self-hosted VEXYL-STT (14 Indian languages) and VEXYL-TTS (22 languages, 44+ voices), plus Sarvam speech recognition, the default cloud recogniser the VEXYL Voice Gateway uses for Indian languages.

Beyond these, VEXYL-STT also covers Assamese, Nepali and Sanskrit, and VEXYL-TTS covers those three plus Bodo, Dogri, Konkani, Maithili, Manipuri, Santali and Sindhi. That makes the self-hosted voice one of the few options for smaller scheduled languages, though you should still test speech recognition separately for any language where only TTS is listed.

A few provider details from the gateway documentation are worth knowing:

• Google’s TTS voices default to Chirp3-HD for the configured languages, but Google publishes no Odia voice, so an Odia turn on Google falls to another configured provider.
• Deepgram’s built-in voices cover English and several European and Asian languages, not Indian languages, so Indian-language callers are better served by another TTS provider.
• Sarvam’s newer TTS model has no dedicated Malayalam or Odia persona, but it is multilingual, so Malayalam text spoken through a Hindi persona still comes out as correct Malayalam.

For a wider comparison of voices, including other open-source models, read our guide to the best text to speech for Indian languages.

Language-by-language notes

Hindi and Hinglish

Hindi has the most mature models and the widest voice choice. The real challenge is Hinglish: callers say “mera order cancel karna hai” or read out English addresses inside Hindi sentences. Decide whether the agent should reply in pure Hindi or natural Hinglish (most callers prefer the latter), and tell the LLM exactly that in the prompt. Our step-by-step guide to building a Hindi voice bot covers prompts and testing, and our Hindi text to speech guide compares voices for calls.

Tamil

Spoken Tamil differs a lot from written Tamil, and callers mix in English (often called Tanglish). Test recognition on colloquial speech, not read-aloud scripts. See our breakdown of Tamil speech to text options for apps and call centres.

Malayalam

Malayalam’s long, agglutinative words make it one of the harder languages for speech recognition, and Manglish is common in Kerala. Phone audio makes this harder still. Our guide to Malayalam speech to text compares cloud APIs, open-source models and self-hosting.

Telugu, Kannada, Bengali, Marathi and Gujarati

All are covered by both the self-hosted VEXYL components and Sarvam’s recogniser. They have fewer public benchmarks than Hindi, so plan an extra round of testing with native speakers from your actual customer base, including different districts and age groups.

Odia, Punjabi, Urdu and smaller languages

Coverage thins out here. Check every component: a language can have a good recogniser but no cloud voice (Odia on Google TTS, for example), or a voice but no tested recogniser. Self-hosted VEXYL-TTS fills several voice gaps.

Code-mixed speech: Hinglish, Tanglish and Manglish

Code-mixing is normal in Indian calls, not an edge case. Three settings help:

• Recogniser mode. Sarvam’s saaras:v3 model, as configured in the VEXYL gateway, offers modes named transcribe, verbatim, codemix and translit, so you can choose how mixed speech is written out.
• Prompt rules. Tell the LLM which script to use and when to keep English words in English (brand names, “EMI”, “OTP”). Text in the wrong script often sounds wrong when spoken.
• Voice choice. Pick a voice that pronounces common English words naturally in an Indian accent, and listen to it reading your real replies.

Choosing the language on each call

A multilingual voice agent in India needs a way to know which language to use from the first second. With the VEXYL Voice Gateway you have several options:

• Per-call language setting. Each call can carry a language_code such as ml-IN or hi-IN, posted as session metadata, sent in a SIP header (X-Language) from your PBX, or set in the outbound call request. A Malayalam DID can therefore go straight to a Malayalam agent.
• Automatic recogniser routing. With the STT provider set to auto, the gateway sends Indian languages (English India, Hindi, Malayalam, Tamil, Telugu, Kannada, Marathi, Gujarati, Bengali, Punjabi, Odia) to Sarvam and other languages to Groq.
• Voices per language. Settings such as SARVAM_TTS_SPEAKER_ML_IN or VEXYL_TTS_SPEAKER_ML_IN pick a different voice for each language, so one bot can speak several languages with the right voice for each.
• Per-language messages. Greeting, transfer, goodbye and timeout messages can have language variants, so even fixed prompts play in the caller’s language.

One caution for realtime speech-to-speech mode: native-audio models ignore the language tag and follow the caller, so you fix the language in the system prompt instead.

Writing prompts for spoken Indian languages

The LLM writes text, but the caller hears speech. A few rules make a big difference:

• Keep replies to one or two short sentences. Long replies feel slower and are harder to follow on a phone.
• Spell out numbers the way people say them. Rupee amounts, dates and phone numbers should be written in the form you want spoken, for example amounts in words in the caller’s language.
• Use the native script. Most Indian-language voices read native script more accurately than romanised text.
• Match the register. Formal Hindi sounds stiff on a delivery call; overly casual Tamil can sound rude to an older patient. Specify the tone.
• Confirm key details. Repeat back dates, times and amounts before acting on them.

How to test a multilingual voice agent

1. Test on phone audio. Call the agent from mobile phones on different networks. Do not judge recognition from uploaded studio files.
2. Use real speakers. Recruit colleagues or customers who speak each language natively, from different regions.
3. Script hard cases. Names, addresses, numbers, code-mixed sentences, interruptions and silence.
4. Read the transcripts. Compare what the caller said with what the recogniser wrote, and note repeated errors.
5. Listen to the voice. Check how it reads amounts, dates and English words in each language.
6. Measure the pause. Streaming recognisers return text while the caller is still talking; batch recognisers wait for silence and add noticeable delay per turn, according to the gateway documentation. Prefer streaming for live calls.

You can try the self-hosted components yourself before building anything: the VEXYL-STT playground for recognition and the VEXYL-TTS demo for voices.

Cloud or self-hosted for Indian languages?

Many teams mix the two: a cloud recogniser for one language where it tests best, and a self-hosted voice where data or cost matters. Because the VEXYL gateway lets you choose providers per language and per call, you do not have to commit to one vendor for everything.

How VEXYL fits

VEXYL is built in India for AI voice and chat agents that speak Indian languages, on your servers or on VEXYL Cloud. Here is what that means for language work specifically:

• Open-source Indian-language speech. VEXYL-STT is a self-hosted speech-to-text server for 14 Indian languages with WebSocket streaming and batch REST, running on CPU with no per-minute fees. VEXYL-TTS is an Apache 2.0 self-hosted text-to-speech server for 22 languages with 44+ voices.
• Your choice of cloud providers. Recognition from Sarvam, Google, Deepgram, Groq or Gemini; voices from Sarvam, Google, Gemini, ElevenLabs, Smallest AI or Azure. Bring your own API keys.
• Language per call and per voice. Set the language by SIP header, metadata or outbound request, and pick a voice per language.
• Any LLM as the brain. Through LiteBot you can use Groq, OpenRouter, OpenAI, Gemini, Sarvam or a local model with Ollama, which keeps conversations on hardware you control.
• Your phone system stays. Connect through a SIP trunk, Asterisk, FreePBX or a supported IP-PBX.

The trade-off is honest: coverage for smaller languages is broader on the voice side than on recognition, and every language still needs testing with your own callers. The free self-hosted Developer edition (4 concurrent calls) is enough to run that test properly.

FAQ

Which Indian languages can AI voice agents speak?

It depends on the providers behind the agent. With the VEXYL stack, recognition covers 14 Indian languages through VEXYL-STT and English (India) plus 10 Indian languages through Sarvam, and voices cover 22 languages through VEXYL-TTS, from Hindi and Tamil to Konkani and Santali.

Can one AI voice agent speak several Indian languages?

Yes. You can set the language for each call and assign a voice per language, so one agent can serve Hindi, Tamil and Malayalam callers. Each language needs its own testing and, ideally, its own instructions in the prompt.

Can an AI voice agent understand Hinglish?

Yes, if the recogniser handles code-mixed speech. Sarvam’s saaras:v3 model in the VEXYL gateway has a codemix mode for this, and the prompt should tell the LLM how to reply in mixed speech.

Is there an AI voice agent for Malayalam or Tamil?

Yes. Malayalam and Tamil are covered by VEXYL-STT, VEXYL-TTS and Sarvam’s recogniser. Test on real phone calls, because colloquial speech and code-mixing are common in both.

Can I run Indian-language voice AI without sending audio to the cloud?

Yes. With self-hosted VEXYL-STT, VEXYL-TTS and a local LLM through Ollama, the full conversation can stay on your own servers.

How accurate is speech recognition for Indian languages on phone calls?

Accuracy varies by language, provider, accent and line quality, so published numbers rarely match your calls. Run a test on your own recordings or test calls and compare providers side by side.

Test your languages on a real call

The only reliable way to choose is to hear your agent speak your callers’ languages. Start with the free self-hosted Developer edition, or contact the VEXYL team to plan a pilot in the languages you need on VEXYL Cloud or on-prem.