Voice Settings

Provider-specific voice configuration for WebSocket streaming.

voice_settings is an object sent in the handshake frame to configure provider-specific parameters:

{
  "text": " ",
  "voice_settings": {
    "voice_speed": 1.2
  }
}

Telnyx Natural

Parameter	Type	Default	Description
voice_speed	float	1.0	Speech rate. Values > 1 are faster.

Telnyx NaturalHD

Parameter	Type	Default	Description
voice_speed	float	1.0	Speech rate. Values > 1 are faster.

Telnyx Ultra

Telnyx Ultra is REST-only — not available over WebSocket. These settings apply to the REST API.

Parameter	Type	Default	Description
voice_speed	float	1.0	Speech rate. Values > 1 are faster.
language_boost	string	—	Target language
volume	float	—	Volume level
emotion	string	—	Emotion: neutral, happy, sad, angry, fearful, disgusted, surprised

Telnyx Qwen3TTS

Parameter	Type	Default	Description
language_boost	string	"Auto"	Target language. Accepted: Auto, English, Chinese, French, German, Italian, Japanese, Korean, Portuguese, Russian, Spanish, or ISO codes (en, zh, etc.)

Azure Speech

Parameter	Type	Default	Description
language_code	string	"en-US"	Language code
text_type	string	"text"	Input type: text or ssml
effect	string	—	Audio effect: eq_car or eq_telecomhp8k
gender	string	—	Voice gender filter: Male or Female

AWS Polly

Parameter	Type	Default	Description
language_code	string	—	BCP-47 language code
output_format	string	—	Audio format override
engine	string	"standard"	Polly engine: standard, neural, generative, long-form
text_type	string	"text"	Input type: text or ssml
lexicon_names	array	—	Pronunciation lexicon names

Minimax

Parameter	Type	Default	Description
speed	float	—	Speech rate
vol	float	—	Volume
pitch	integer	—	Pitch adjustment
language_boost	string	—	Language emphasis

Inworld

Parameter	Type	Default	Description
language_code	string	—	Language code