Expression

Emotion spans

Wrap text in curly-brace emotion tags to control prosody and voice routing. Each emotion maps to a specific voice and speed:

{joy}Great news!{/joy} But {calm}let me explain.{/calm}

Eight emotions available: neutral, serious, friendly, professional, calm, joy, urgent, whisper.

Emotions can be mixed across a sentence for nuanced delivery. Untagged text defaults to neutral. Unknown emotion names fall back to neutral with a warning.

SSML-lite

A simplified subset of SSML for timing and emphasis control — without the full complexity of the SSML spec:

• <break time="500ms"/> — Pause for a duration
• <emphasis level="strong">word</emphasis> — Emphasize a word or phrase
• <prosody rate="slow">text</prosody> — Control speaking rate

SFX tags

Inline sound effects that play alongside speech:

Tag	Sound
[ding]	Notification chime
[chime]	Gentle bell
[whoosh]	Swoosh transition
[tada]	Celebration fanfare
[pop]	Short pop sound
[click]	Button click

Enable SFX with sfx: true in voice_speak (on by default).

Combining expression features

All expression features can be combined in a single synthesis request:

{joy}Welcome to the show!{/joy} <break time="300ms"/>
{calm}Today we'll be discussing...{/calm} [ding]