What is Soniox TTS?
Soniox Text-to-Speech is a real-time speech synthesis platform built for conversational AI. Itstts-rt-v2 model streams speech as the reply is being generated, so audio starts playing before the full sentence is ready.
One model covers every supported language and voice, so a multilingual agent does not need a different model per language.
Key Features of Soniox TTS
Soniox TTS offers several features that make it well suited to real-time voice agents: Broad Multilingual Coverage from One Model: Speaks 63 languages, including ten Indian languages, without switching models. Real-Time Streaming Synthesis: Audio is produced as the reply arrives rather than after it completes, keeping responses quick in live conversation. Large Named Voice Catalogue: 200 built-in voices per model, addressed by name rather than by an opaque id, spanning a range of accents and speaking styles. Voice Cloning: Clone a voice in your own Soniox account and put it on an agent by passing its id. Delivery Controls:speed adjusts pace between 0.7 and 1.3, and reduce_silence tightens the pauses inserted between sentences.
How Bolna Uses Soniox for TTS
Bolna AI integrates Soniox’s real-time synthesis to produce the spoken side of its voice agents. Here’s how Bolna leverages Soniox TTS: Streaming Speech for Natural Conversation Flow: Bolna speaks Soniox audio as the reply is generated rather than waiting for the whole response, so agents answer without the pause that makes automated calls feel stilted. Responsive Barge-In: When a caller interrupts, the agent stops mid-sentence and drops the rest of the utterance cleanly, so it starts listening instead of talking over them. Multilingual Agents on a Single Voice Provider: Because one Soniox model covers every supported language, Bolna agents can serve callers across languages without changing synthesizer per language. Consistent Quality on Telephony and Web: Bolna delivers Soniox audio at the quality each channel expects, so the same agent sounds right on a phone call and in the browser.List of Soniox TTS models supported on Bolna AI
Voices
Soniox addresses its built-in voices by name rather than by an opaque id, sovoice and voice_id carry the same value - Adrian, not a UUID. Both fields are required in provider_config, so send the name twice. Point voice_id at a cloned voice’s id to use a clone instead; it takes precedence when the two differ.
A few of the voices in the catalogue:
A voice that is not in the catalogue is rejected when the agent is saved.
Supported Languages
Onetts-rt-v2 model speaks 63 languages, so a multilingual agent can keep a single synthesizer across its whole language range instead of switching providers per language.
Indian languages: Hindi (hi), Bengali (bn), Tamil (ta), Telugu (te), Gujarati (gu), Kannada (kn), Malayalam (ml), Marathi (mr), Punjabi (pa), Urdu (ur)
Other languages: major European, Asian and Middle Eastern languages are supported too, including English, Spanish, French, German, Arabic, Japanese and Chinese.
Set the language in provider_config.language using its plain ISO code: hi, not hi-IN. Browse every language, and the voices available for each, in the Languages tab.
Configuration
speed and reduce_silence are only sent when you set them; left out, each uses Soniox’s own default for the model. speed is validated when the agent is saved, so a value outside 0.7 to 1.3 is rejected at agent setup rather than failing mid-call. See the Create Agent API for every synthesizer field.
Conclusion
Soniox TTS gives Bolna agents real-time streaming speech across a wide language range from a single model, with a large named voice catalogue and cloning for teams that want a distinct voice identity. For related integrations:- Combine with the Soniox transcriber for a complete Soniox integration
- Give each language its own voice with multilingual support
- Compare against other providers in the synthesizer comparison
- You can also connect your own Soniox account and use it with Bolna AI