AssemblyAI WebSocket TTS provider

This page applies when provider=assemblyai — either via the voice compound parameter or by setting provider=assemblyai explicitly. See Configuration.

Voice Format

AssemblyAI.assemblyai-tts-1.<VoiceId>

Example: AssemblyAI.assemblyai-tts-1.aai-jane

Models

Model	Description
`assemblyai-tts-1`	Streaming model. Default and the only model accepted.

Voices

11 voices under assemblyai-tts-1; every voice speaks all six supported languages. The list is on the AssemblyAI provider page, or browse it via the Voices API.

Language

Set voice_settings.language on the init frame, or the language query parameter, to the two-letter ISO 639-1 code of the text: en, es, de, fr, it, or pt. The default is en. AssemblyAI does not detect the language, and any other language is rejected with an error.

Voice Settings

Field	Type	Default	Description
`language`	string	`en`	Two-letter ISO 639-1 code of the text.

{
  "text": " ",
  "voice_settings": {
    "language": "fr"
  }
}

SSML is not supported, and there are no speed, pitch, or emotion controls. Send plain text.

Audio Output

Streamed delivery. Default: MP3 at 24 kHz. Use the audio_format and sample_rate query parameters to change the output:

`audio_format`	Accepted Sample Rates (Hz)	Default
`mp3`	8000, 16000, 22050, 24000, 44100, 48000	24000
`wav`	8000, 16000, 22050, 24000, 44100, 48000	24000
`linear16`	8000, 16000, 22050, 24000, 44100, 48000	24000
`mulaw`	8000, 16000, 22050, 24000, 44100, 48000	8000
`alaw`	8000, 16000, 22050, 24000, 44100, 48000	8000

wss://api.telnyx.com/v2/text-to-speech/speech?voice=AssemblyAI.assemblyai-tts-1.aai-jane&audio_format=mulaw

Limits

A request accepts up to 5,000 characters. Split longer text into several requests. AssemblyAI is a third-party provider that synthesizes speech in the United States. Requests that require in-transit data locality are refused. See Data Residency.

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AssemblyAI WebSocket TTS provider

Voice Format

Models

Voices

Language

Voice Settings

Audio Output

Limits

​Voice Format

​Models

​Voices

​Language

​Voice Settings

​Audio Output

​Limits

Voice Format

Models

Voices

Language

Voice Settings

Audio Output

Limits