Text-to-Speech
On Device AI includes powerful text-to-speech capabilities for converting any text into natural-sounding speech. Choose between Apple's built-in voices and the advanced Kokoro TTS engine.
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TTS Engines
Two text-to-speech engines are available:
- Apple Voices: Uses the system's built-in speech synthesis. Many voices available, lightweight, and fast.
- Kokoro TTS: Advanced neural TTS engine that produces more natural, human-like speech. Runs entirely on-device. Requires downloading the Kokoro voice model (~80MB).
💡 Tip
Kokoro TTS produces significantly more natural speech than Apple voices. Download it in Settings → Voice to hear the difference.
Using TTS
There are several ways to use text-to-speech:
- TTS Tab: Navigate to the Text to Speech tab, paste or type text, and tap the play button
- AI Chat responses: Tap the speaker icon on any AI response to have it read aloud
- Message Actions: Select "Send to TTS" from a message's context menu (iOS) or the "More Actions" button (macOS) to send it directly to the TTS tab
- Auto-play: Enable auto-play to have every AI response spoken automatically
Speech Speed
Adjust the speech speed in Settings → Voice:
- Range: 0.5x (slow) to 2.0x (fast)
- Default: 1.0x (normal speed)
- Test button: Preview the current speed setting before applying
Auto-Play Responses
When enabled, AI responses in chat are automatically converted to speech and played back. This creates a hands-free conversational experience, especially useful when combined with voice input.
Toggle auto-play in Settings → Voice → "Auto-play voice responses".