Gemini 3.8 Flash TTS
Advanced text-to-speech with natural language voice design and line-by-line performance direction
Context window
8192 tokens
Input / 1M tokens
$0.50
Output / 1M tokens
$9.00
Provider
Data verified 2026-09-24
Gemini 3.8 Flash TTS is a text-to-speech model built for deep creative direction and character design. It creates entirely new voices from scratch using natural language prompts and enables granular line-by-line control over acting cues, pacing, dialect shifts, and backchanneling across 130+ languages.
Capability index
Relative estimates (0-100) to place this model against its peers, grounded in published benchmarks.
How to access it
Available through Gemini API and Google AI Studio. Introductory pricing through December 31, 2026.
Strengths
- ✓Natural language voice design from scratch
- ✓Voice replication from 30-second audio samples
- ✓Fine-grained line-by-line performance control
- ✓130+ language support
- ✓Built-in SynthID watermarking for security
- ✓#1 on Hume AI Voice Design Benchmark
Best for developers who...
When to choose it (and when not to)
Reach for Gemini 3.8 Flash TTS when...
- →When voice quality and expressiveness are critical
- →When custom character design and acting direction are needed
- →For professional creative content production
Look elsewhere if...
- ✕When cost efficiency is the primary concern (use Flash-Lite instead)
- ✕For high-volume, commodity speech generation
- ✕When latency is time-critical
How to use it
- ›Describe voice characteristics in natural language for voice design
- ›Use performance direction annotations for line-by-line control
- ›Provide accent, tone, and emotional context in prompts
Quickstart
Pythonfrom google.generativeai import GenerativeModel
model = GenerativeModel('gemini-3.8-flash-tts')
response = model.generate_speech(text='Hello world', voice_config={'voice_description': 'young female, warm tone'})Requires google-generativeai library and API key
API model id: gemini-3.8-flash-tts
Benchmarks
| Benchmark | Score | Notes |
|---|---|---|
| Hume AI Voice Design Benchmark | #1 | Top ranking in voice design quality |
| Voice Arena | Near top | Near top rankings in Japanese, Hindi, and Mexican Spanish |
Source: DeepMind official announcement
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