Sonex Labs vs Deepgram: which fits a team that needs Indian languages in both directions? (2026)

Why do teams compare Deepgram with Sonex Labs?

Many teams reading this already use or have shortlisted Deepgram for speech to text. The question usually appears later, when a product that started in English has to serve callers in India or other multilingual markets. At that point the team discovers that transcription and speech synthesis are two different coverage problems. A provider can understand Hindi and still have no Hindi voice.

So the useful question is whether one provider covers every language your users speak, in both directions, on a phone line, at a workable cost and latency. This article compares Deepgram's Nova-3, Flux, Aura-2 and Voice Agent API with Sonex Labs' Valmiki speech to text, Pāṇini text to speech and voice agents from that angle, with every price dated and every Deepgram figure linked to its source.

What are Sonex Labs and Deepgram?

Sonex Labs is a voice platform built around the languages most speech APIs cover thinly or not at all. Pāṇini, our text-to-speech model, speaks more than 250 languages in 34 writing systems, including 36+ Indian languages and dialects such as Bhojpuri, Marwari, Garhwali, Maithili, Saraiki, Bundeli, Braj, Angika and Bhili (languages). Valmiki, our speech-to-text model, covers more than 100 languages (speech to text). The voice agent platform combines both with telephony on Sonex numbers and a language model of your choice. Pricing is per character, per minute of audio billed by the second, and per agent minute (pricing).

Deepgram is a voice AI API company known for speech to text. Its transcription models are Nova-3, for streaming and pre-recorded audio, and Flux, a streaming model for voice agents that decides when a speaker has finished their turn (Deepgram models and languages, Flux docs). It also sells Aura-2 text to speech and a Voice Agent API, a WebSocket API that handles the full pipeline of listening, thinking and speaking (Voice Agent API docs). Pricing is usage-based, on pay as you go or a prepaid Growth plan (Deepgram pricing, checked 24 October 2026).

What should decide it for a multilingual team?

The first factor is language coverage in each direction, checked separately. List every language and dialect your callers use and check it against both the transcription list and the voice list; a gap in either means a second vendor, a second contract and a second latency budget.

The second is how each system sounds and listens on a real phone line, especially for names, numbers, dates and mid-sentence language switches. Third is latency at the caller's ear, carrier included. Fourth is total monthly cost at your volume, including telephony, plan minimums and any second voice provider. Fifth is where the system can run, if your data must stay in your own cloud. Last is what you have to build yourself around the model, starting with phone numbers.

Sonex Labs and Deepgram at a glance

Which can both listen and speak in your customers' languages?

Pāṇini speaks more than 250 languages across 34 writing systems, and its 36+ Indian languages and dialects go below the state-language level to Bhojpuri, Marwari, Haryanvi, Chhattisgarhi, Mewari, Garhwali, Maithili, Saraiki, Bundeli, Braj, Angika and Bhili (languages). Every language costs the same $0.03125 per 1,000 characters, and every language page has a live playground, so you can hear your own script before signing up (text to speech).

Pāṇini has 120 platform voices and clones a voice from a 10-second sample, and a voice or clone can speak across languages (text to speech). It reads mixed-language text such as Hinglish naturally in one voice. For listening, Valmiki covers more than 100 languages and detects the spoken language automatically (speech to text). Confirm each language and dialect you need in both directions, including the way your callers mix languages mid-sentence.

Deepgram's coverage is split between the two directions. On transcription, Nova-3 lists Assamese, Bengali, Gujarati, Hindi, Kannada, Marathi, Punjabi, Tamil, Telugu and Urdu among roughly sixty languages and variants, and Nova-3 multilingual handles code-switching across 55 languages, including Hindi, Bengali, Gujarati, Kannada, Marathi, Tamil and Telugu (Deepgram models and languages, code-switching, checked 24 October 2026). Malayalam and Odia are not in the monolingual list. On speech, Aura-2 voices cover seven languages, English, Spanish, German, French, Dutch, Italian and Japanese, most of its roughly ninety voices are English, and the models page does not mention cloning (Deepgram TTS models). A Hindi or Tamil agent on Deepgram therefore needs a second provider for its replies.

How do they sound and respond on a real phone call?

Pāṇini is trained for 8 kHz phone audio and starts streaming audio in under 200 milliseconds (time to first byte), and Sonex voice agents answer in about 300 milliseconds end to end, from when the caller stops speaking to when the agent starts (text to speech). Deepgram states under 200 milliseconds to first byte for Aura-2 (Aura-2 announcement) and about 260 milliseconds for Flux to detect the end of a turn (Flux docs); we did not find an end-to-end figure for its Voice Agent API. All of these are vendor-reported and measured differently, so measure at the caller's ear.

On accuracy, Deepgram has published more. It reports a median word error rate of 6.84% streaming and 5.26% batch for Nova-3, on 81.69 hours of audio across domains such as phone calls and meetings, vendor-reported and not broken out for Hindi or Tamil (Nova-3 announcement). Sonex Labs has not published a WER or MOS benchmark, which is why the test plan at the end of this article matters: it measures both on your own calls.

What does a full voice pipeline cost per month?

Sonex Labs charges $0.00525 per minute of audio for Valmiki transcription, billed by the second. Pāṇini is $0.03125 per 1,000 characters, or $0.028125 on the $5 a month plan, the same in every language. Voice agents are $0.055 a minute on pay as you go, including speech to text, text to speech and telephony on Sonex numbers; bring your own telephony and no minute charge applies to it. Bring your own LLM key at zero markup or use our Vyas LLM. The free tier includes 10,000 characters and one voice clone, no card required (pricing, checked 24 October 2026).

Deepgram marks its streaming transcription prices as limited-time promotional rates, with no end date given (Deepgram pricing, checked 24 October 2026). On pay as you go, Nova-3 monolingual is $0.0048 a minute (regular $0.0077) and Nova-3 multilingual $0.0058 (regular $0.0092); Flux multilingual is $0.0078. Growth rates start at $0.0042 for Nova-3 monolingual, also promotional, with a $4,000 a year prepaid minimum, which puts English transcription below our rate. Aura-2 costs $0.030 per 1,000 characters. The Voice Agent API is billed on WebSocket connection time at $0.075 a minute Standard, $0.065 with your own TTS or LLM, $0.050 with both, and $0.163 Advanced; its telephony guide bridges calls from Twilio, so carrier charges come from your carrier (Deepgram telephony guide). New accounts get $200 of credit.

The worked examples use pay-as-you-go list prices, streaming transcription and three-minute agent calls. Language model costs are left out on both sides, since you would pay for the same model either way. Deepgram's agent rows exclude carrier charges, which you arrange separately (Deepgram telephony guide).

Once a product needs agents, or speech in a language Aura-2 does not cover, the Sonex figure is the whole bill apart from the language model, while the Deepgram figure still has a carrier and, for Indian languages, a second voice vendor to add. Sonex's rates are standard list prices rather than promotional ones.

Which is built for phone calls?

The Sonex agent price includes telephony on Sonex numbers, so a team can run calls without a separate carrier account, and still bring its own telephony, with no minute charge from us, when it already has one. Platform capacity is 10,000 concurrent sessions; ask us for your account's limit. You choose your own LLM key or our Vyas LLM (pricing). Agents can transfer a live call to a human agent, use MCP and tool calling, and connect to HubSpot, Salesforce, n8n, Zapier and Make. Calls can be recorded and transcribed, and outbound campaigns take calling windows, time zones and retry limits.

Deepgram's Voice Agent API is a WebSocket API that listens, calls a language model and speaks, with function calling for tool use (Voice Agent API docs). It is an API rather than a call platform: its telephony guide has your own server bridge a Twilio call to Deepgram, so numbers and carrier billing stay with Twilio (Deepgram telephony guide). Pay-as-you-go concurrency is 45 agent sessions, 60 on Growth (Deepgram pricing). Self-hosting of speech to text and text to speech is available with an Enterprise plan or through AWS SageMaker (Deepgram self-hosted).

When is Sonex Labs the better choice?

Sonex Labs is the better choice when your callers need to hear their own language spoken back and that language is not one of Aura-2's seven. That covers Hindi, Tamil, Telugu and the other major Indian languages, and it extends to dialects such as Bhojpuri, Marwari, Garhwali, Maithili or Bundeli and the rest of a 250+ language list, all at the same $0.03125 per 1,000 characters as English (languages, pricing).

It suits teams that want one provider for speech to text, text to speech and agents: one contract, one bill and one place to debug, rather than a transcription vendor, a voice vendor and a carrier. Live transfer to a human agent, call recordings and transcripts, and CRM connectors are part of the same platform. A brand voice can be cloned from a 10-second sample, and one clone is included in the free tier (text to speech).

It also suits teams running calls at volume. The $0.055 a minute agent rate includes telephony on Sonex numbers, bring-your-own telephony carries no minute charge, and your own LLM key runs at zero markup, which makes the monthly cost straightforward to forecast. Our rates are standard list prices rather than promotional ones (pricing).

When is Deepgram the better choice?

Deepgram is the better choice when your audio is mostly English or another single major language, you only need transcription, and you want published benchmarks for a procurement review: its promotional Nova-3 rates are below ours for English, and it documents self-hosting. Its Growth plan suits teams that can commit to the prepaid minimum, and specialised models such as Nova-3 Medical serve regulated transcription work (Deepgram models and languages). Teams that want to tune turn-taking themselves will also find Flux's configurable end-of-turn thresholds well documented, alongside a large set of SDKs and integration guides (Flux docs).

How should you test both before deciding?

Neither side's numbers were measured on your audio, so run a short bake-off. Collect fifty to a hundred real call recordings per language, including noisy lines and callers who switch languages, and have a native speaker produce reference transcripts. Run them through Nova-3 or Flux and through Valmiki with the same settings, and score word error rate separately for the words that cost you money when they are wrong: names, phone numbers, amounts, dates and addresses.

For speech, write one script per language that includes those same hard items, synthesise it with each provider you are considering, and ask native listeners to rate it blind on a phone line rather than headphones. For agents, place at least twenty test calls per configuration over the same carrier and measure the gap between the caller finishing and the first audible reply, at the caller's end. Deepgram's $200 credit and our 10,000 free characters cover most of this.