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Release notes

Introducing Telnyx Ultra voice

16, Mar 2026

Telnyx Ultra is a new premium voice model now available in Telnyx text-to-speech. It generates expressive speech across 36 languages with sub-100 ms time to first byte, and can be used through the standalone TTS API or inside Portal AI Assistants.

What's New

  • Telnyx Ultra TTS model: Premium speech synthesis with expressive prosody and natural pacing.
  • Sub-100 ms time to first byte: Low-latency audio generation for real-time voice AI conversations.
  • 36 language support: Multilingual text-to-speech output for global deployments.
  • SSML emotion tags: Control tone, pacing, and emphasis using Speech Synthesis Markup Language.
  • Portal AI Assistant integration: Select Ultra voices inside Portal-configured AI agents.
  • Standalone TTS API: Generate speech programmatically through the Telnyx text-to-speech API.

Why It Matters

  • Faster voice AI responses: Sub-100 ms latency keeps conversations natural and reduces caller drop-off.
  • More realistic speech: Controllable emotional tone through SSML makes automated voices sound human.
  • One API for everything: Use the same TTS model across standalone API calls and Portal AI Assistants.
  • Global reach: 36-language support for multilingual voice applications without switching providers.
  • Better caller experience: Natural speech improves engagement in AI assistants, IVR prompts, and outbound calls.

Use Cases

  • AI phone assistants: Real-time speech generation during live voice conversations.
  • Customer support IVR: Natural-sounding prompts and menu navigation.
  • Multilingual voice apps: Text-to-speech in 36 languages for global products.
  • Automated notifications: Outbound calls and reminders with expressive, human-like voice.

Getting Started

Telnyx Ultra TTS.gif

  1. Choose a Telnyx Ultra voice from the supported voice list.
  2. Call the TTS API to generate speech, or select an Ultra voice in your Portal AI Assistant settings.
  3. Pass your text payload to synthesize audio.
  4. Optionally add SSML tags to control pacing, emphasis, and emotion.

Read the developer documentation or contact your Telnyx team to get started.