Gemini 3.8 Flash TTS
Google · Released Sep 2026
Conditional. Gemini 3.8 Flash TTS is Google's flagship text-to-speech model, available in the Gemini API with voice design, consented voice replication and SynthID watermarking on every clip. The deciding caveat is cost: today's paid rates are launch prices that double when the launch window closes, and its Hume AI leaderboard placements are Google-reported, not measured by us. Suits developers building expressive narration, character voices or dubbing who can budget for the post-launch rate.
Is it right for you?
Good for
- Expressive narration and character voices; Google's model page calls it a flagship creative model for studio-grade voice fidelity, expressive acting and voice design
- Voice replication from a 30-second sample with consent verification, SynthID and C2PA credentials; persistent custom voices up to 200 per project with a 1-year TTL
- Multilingual speech: over 130 languages per Google's model and speech docs
- Two-speaker dialogue in a single request using prebuilt voices
Not good for
- Voice replication through Google AI Studio for users in Illinois, Texas, the EEA, the UK, Switzerland or India, where Google does not offer it
- Dialogue with more than two speakers in one request
- Anything beyond text in, audio out; the TTS models accept text only and return audio only
- Budgets built on the launch rate, which is priced through December 31, 2026 and doubles from January 1, 2027
How it performs by task
Expressive narration and voice design
Google positions it for expressive acting and voice design and reports top placement on Hume AI's Voice Design Benchmark; vendor-reported, untested by us
Voice cloning
30-second replication with consent checks and watermarking, but Google does not offer it through AI Studio in the EEA, UK, Switzerland, India, Illinois or Texas
Multi-speaker dialogue
Supported, capped at two speakers per request with prebuilt voices
Pricing
Input
$0.50 / 1M (text)
Output
$9.00 / 1M (audio)
Context
Launch rate to 2026-12-31; $1/$18 from 2027
Benchmarks
No verdict changes yet
The clock starts day one — changes land here as our verdict evolves.
Sources
- Google blog: Gemini 3.8 text-to-speech models (Sep 23, 2026)Oct 2026
- Gemini API docs: PricingOct 2026
- Gemini API speech generation docsSep 2026
- Gemini API modelsSep 2026
Verification log
- Pricing— No changes
Automated agent