Gemini TTS#

Generate speech audio from text using Gemini TTS models. The default is Gemini 3.1 Flash TTS Preview, and the script still supports Gemini 2.5 preview TTS models when you pass -m.

What this skill does#

• Single-speaker text to speech
• Two-speaker podcast-style audio
• Style control with natural language prompts
• WAV output that can be sent directly in chat or used in apps

Files#

• scripts/gemini_tts.sh: CLI wrapper around the Gemini REST API

Quick start#

bash

# Show all options
scripts/gemini_tts.sh --help

# Single speaker, default voice (Kore)
scripts/gemini_tts.sh "Hello, welcome to the show!"

# Pick a voice
scripts/gemini_tts.sh -v Puck "This is Puck speaking."

# With style control
scripts/gemini_tts.sh -s "Say in a warm, calm tone:" "Take a deep breath."

# Save to a specific file
scripts/gemini_tts.sh -o /tmp/greeting.wav "Hey there!"

# Multi-speaker conversation
scripts/gemini_tts.sh --multi "Host:Kore,Guest:Puck" \
  "Host: Welcome to the podcast! Guest: Thanks for having me."

The script prints the output WAV file path.

Models#

ModelBest forgemini-3.1-flash-tts-preview (default)Best default now: low-latency, natural output, expressive narrationgemini-2.5-flash-preview-ttsBackward-compatible fast preview modelgemini-2.5-pro-preview-ttsLong-form narration and higher-end creative work

Current note: Gemini 3.1 Flash TTS Preview is live and should be the default path for this skill. Gemini 2.5 preview TTS models remain useful as compatibility fallbacks.

Preview model note: gemini-3.1-flash-tts-preview is a preview model. If Google renames or retires it, pass -m gemini-2.5-flash-preview-tts as a fallback, or check the current model list.

Switch model examples:

bash

scripts/gemini_tts.sh -m gemini-2.5-pro-preview-tts "Your text here"
scripts/gemini_tts.sh -m gemini-2.5-flash-preview-tts "Your text here"

Voices#

Available prebuilt voices:

Zephyr, Puck, Charon, Kore, Fenrir, Leda, Orus, Aoede, Callirrhoe, Autonoe, Enceladus, Iapetus, Umbriel, Algieba, Despina, Erinome, Gacrux, Pulcherrima, Achird, Zubenelgenubi, Vindemiatrix, Sadachbia, Sadaltager, Sulafat, Laomedeia, Achernar, Schedar, Rasalgethi, Nashira, Enif

The same 30-voice library is shared between gemini-3.1-flash-tts-preview and the gemini-2.5-flash-preview-tts / gemini-2.5-pro-preview-tts fallbacks, so a voice you pick for the default model will still work if you drop back to a fallback via -m.

Style control#

Gemini 3.1 Flash TTS reads plain transcripts naturally, but gives you two complementary ways to steer the delivery when you want more control.

Inline audio tags#

Drop bracketed directions into the transcript. They modify what follows, can appear anywhere, and can stack or repeat across a single script:

text

[excitedly] Massive update today — [whispers] but keep it between us. [laughs]

Tags are open-ended; anything in [ ] is treated as a direction to the model. A useful starting set:

• Emotion — [excitedly], [bored], [reluctantly], [amazed], [curious], [mischievously], [panicked], [sarcastic], [serious], [tired], [trembling]
• Pace and volume — [very fast], [very slowly], [asmr], [deep and loud shouting], [whispers]
• Non-verbal — [gasp], [giggles], [sighs], [snorts], [cough], [laughs], [crying]
• Character / style — [like dracula], [like a dog], [singing], [sarcastically, one painfully slow word at a time]

Structured context prompt#

For longer pieces where you want a consistent persona, prepend an AUDIO PROFILE / SCENE / DIRECTOR'S NOTES / TRANSCRIPT block. The four headers are load-bearing — the model uses them to separate performance context from the script it should actually speak:

text

# AUDIO PROFILE: Jaz, London morning-show radio DJ

## THE SCENE: 10 PM, neon-lit studio, "ON AIR" tally blazing.
Jaz is bouncing on their heels, hands on the faders, infectious energy.

### DIRECTOR'S NOTES
Style: vocal smile always audible; punchy consonants; elongated vowels on excitement words.
Accent: Brixton, London.
Pace: energetic, bouncing cadence, no dead air.

#### TRANSCRIPT
[excitedly] Yes, massive vibes in the studio! [shouting] Turn it up!

Inline tags inside #### TRANSCRIPT override the baseline direction when you want a specific beat.

Tips#

• Keep the script and direction coherent — the speaker, what is said, and how it is said should agree.
• Don't overspecify. Give the model space to fill gaps; it reads better.
• A simple preamble ("Say cheerfully: ...") still works for quick one-offs, but inline tags give you per-phrase control and structured prompts give you persona consistency.

Full prompting reference: Gemini speech-generation docs.

Multi-speaker#

Up to 2 speakers. Use --multi "Name1:Voice1,Name2:Voice2" and make sure the speaker names in the text match.

Supported languages#

70+ languages are supported, including Arabic, Bengali, Chinese, English, French, German, Hindi, Indonesian, Italian, Japanese, Korean, Portuguese, Russian, Spanish, Turkish, Ukrainian, Urdu, Vietnamese, and many more. See the Gemini speech-generation docs for the full locale list.

Limitations#

• Audio output only
• Maximum 2 speakers in multi-speaker mode
• Preview model names may change
• No SSML support
• No custom voice cloning

Verification#

Basic smoke test once your API key is set:

bash

export GEMINI_API_KEY=your_key_here   # GOOGLE_API_KEY is also accepted
scripts/gemini_tts.sh -o /tmp/gemini-test.wav "This is a Gemini TTS smoke test."
file /tmp/gemini-test.wav

Expected result: a playable WAV file is created (24 kHz mono, 16-bit PCM WAV).