Practice Preview
$0 / forever
Verify your room acoustics and run your first scored Vietnamese tone-pair loop with zero account setup required.
- Quiet-room local recording check before scoring
- First DSP PASS / FAIL / ABSTAIN verdict free on /practice
- 6-tone reference guide & minimal-pair contrast previews
Đúng Chưa Pro
$9/mo
Built for serious Vietnamese learners who want honest F0 pitch and glottal contour feedback between tutor sessions.
- Unlimited tone practice drills across all 6 Vietnamese tones
- Southern & Northern voice coaching (male & female reference baselines)
- Personalized tone error history & cross-device cloud sync
- Minimal-pair contrast suites (Hỏi vs Ngã, Sắc vs Ngã, Sắc vs Nặng)
- Abstains on noisy audio — never gives fake fluency scores
How billing & access work
Instant Stripe checkout: Clicking Subscribe — $9/mo opens our live Stripe checkout (`https://buy.stripe.com/00w6oHelM5iZ64c7Em2B20j`). Subscriptions renew monthly at $9 USD and can be cancelled anytime in one click.
Why does Đúng Chưa abstain on bad audio? Background noise and clipping corrupt fundamental frequency (F0) tracking. Rather than guessing and giving you a fake pass or fail, our DSP gate asks you to re-record cleanly.