Terms of Service

Pengu · Effective 23 July 2026 · Last updated 23 July 2026 · Bản tiếng Việt

This is the agreement (End User License Agreement) between you and Pengu covering the website tiengtrungapp.com, the web app nhamay.tiengtrungapp.com, and the Pengu mobile apps on the App Store and Google Play (for example Pengu Tiếng Trung) — together, the “Service”. By installing or using the Service you agree to these terms. If you do not agree, please do not use the Service.

The 30-second version: Lessons are free. Practice sessions unlock by watching a short ad, or by buying Premium to remove ads. Premium plans are one-time purchases that do NOT auto-renew. Payments are processed by Apple/Google and refunds follow their policies. You can delete your account at any time via Profile → Delete account.

1. Eligibility

You must be at least 13 years old. If you are between 13 and 16, you need consent from a parent or guardian.
You agree that the information you give Pengu is accurate and that you are not impersonating anyone.
If you use the Service on behalf of an organisation, you confirm you are authorised to bind that organisation.

2. What the Service is

Pengu is a suite of Chinese-learning apps for Vietnamese workers: structured lesson paths, vocabulary, dialogues, exercises, spaced repetition and pronunciation practice. All lesson content is provided free of charge. Pengu may add, change, suspend or remove features and content at any time.

3. Accounts

You can use every lesson without an account. An account is required only to buy Premium or use the Invite-a-friend feature.
Accounts are created with an email address or phone number plus a password, and are shared across the whole Pengu app suite.
One account, one device at a time: signing in on a new device ends the session on the previous one.
You are responsible for keeping your password secure and for activity under your account. If you suspect unauthorised access, change your password and tell us at hotro@tiengtrungapp.com.
You may delete your account at any time via Profile → Delete account. See section 6.5 and section 10 of the Privacy Policy for the consequences.

4. Advertising

Practice sessions unlock by watching a rewarded ad served by Google AdMob — this funds our servers and new lessons.
Pengu does not control third-party ad content and is not responsible for the products or services advertised. If you see an inappropriate ad, please tell us.
You may not use technical means to bypass, spoof or automate ad viewing.
Buying Premium removes ads from the app entirely.

5. Premium and payments

5.1 What Premium is

Pengu offers one-time purchase Premium plans: time-limited plans (for example 1 month and 3 months, whose days stack if you buy again) and a lifetime plan.
These are not subscriptions and do NOT auto-renew. We never charge you again automatically; to keep Premium after a plan expires you must buy it again yourself.
Premium benefits: ad-free use plus any benefits listed on the purchase screen at the time you buy.
Premium is tied to your Pengu account and to the individual app you bought it in — buying in one Pengu app does not grant it in another.

5.2 Prices and payment

Prices are shown on the in-app purchase screen at the moment you buy, including taxes as handled by the app store. Prices may change over time; changes apply only to purchases made afterwards.
Payments are processed by Apple App Store or Google Play and charged to your store account. Pengu never sees or stores your card or bank details.
Purchases are verified with Apple/Google servers before benefits are unlocked. If the network fails, the app retries; if benefits still do not appear, use Restore purchases or contact support.
Partner discount codes are valid only while unexpired and entered as instructed in the app.

5.3 Refunds

Because payments are processed by the app stores, refunds follow Apple's and Google's policies:
- iOS: reportaproblem.apple.com
- Android: “Orders & subscriptions” in your Google Play account
If you were charged but did not receive Premium, contact hotro@tiengtrungapp.com within 30 days with your transaction ID — we will unlock the benefit or help you request a refund.
Nothing in this section limits your rights under Vietnamese consumer protection law.
If you delete your account yourself, any remaining Premium is forfeited and is not refunded.

6. Acceptable use

6.1 You may

Use the Service for your personal learning, including for your own job.
Share links and screenshots of lessons with friends and colleagues — we welcome it.

6.2 You may not

Bulk-copy, resell, republish or distribute lesson content (text, audio, images) as your own — including for paid teaching — without Pengu's written permission.
Reverse engineer, decompile or tamper with the app, or circumvent the advertising or Premium-entitlement mechanisms.
Use bots, scripts, emulators or multiple devices to farm Invite-a-friend rewards or other promotions.
Attack, scan, overload our servers or exploit security vulnerabilities.
Use the Service for any purpose that breaks the law of Vietnam or of your country of residence.

6.3 Your content

Pronunciation recordings stay on your device and are never uploaded to Pengu servers (see section 4 of the Privacy Policy). For feedback and bug reports you send us, you grant Pengu a free licence to use them to improve the product.

6.4 Invite-a-friend and referral partners

Invite rewards are granted per device and can be claimed once per device. Pengu may revoke rewards, discount codes and commissions where fraud is detected. Separate terms for the referral partner programme are published on the partner page.

6.5 Breach and termination

Pengu may suspend or terminate your account if you breach these terms or if required by law. For minor breaches we will warn you first. You may end this agreement at any time by deleting your account and uninstalling the app.

7. Licence

Pengu grants you a personal, limited, non-exclusive, non-transferable, revocable licence to install and use the app on devices you own or control, in accordance with these terms and the rules of the relevant app store. All intellectual property rights in the app, the lesson content, the Pengu brand and mascot remain with Pengu. These terms transfer no ownership to you.

8. Learning content — limitations

Content is written by the Pengu team and grounded in real factory and everyday situations. However:

The “Vietnamese-style reading” is an approximate transcription that helps beginners; it does not replace correct pronunciation and is not an official romanisation system.
Pronunciation scores are indicative only and depend on your microphone and your operating system's speech recognition.
Pengu makes no guarantee that you will reach a particular level, pass an exam or obtain a job outcome, and is not responsible for decisions (exams, employment contracts, transactions) made solely on the basis of lesson content.

9. Third-party services

The Service relies on third-party infrastructure and services (Cloudflare; Google — AdMob, Firebase, Play Billing; Apple — App Store, StoreKit). Your use of those services is also governed by their own terms and policies. Pengu is not responsible for third-party conduct.

10. Updates and availability

Pengu may release updates and may require you to update to a minimum supported version to keep using the app when an older version is no longer secure or compatible with our servers.
Lesson content is downloaded online; the first launch requires an internet connection.
We work to keep the Service stable but do not guarantee uninterrupted, error-free operation, and may suspend the Service for maintenance.

11. Disclaimer of warranties

To the maximum extent permitted by law, the Service is provided “as is” and “as available”, without warranties of any kind, express or implied, including merchantability, fitness for a particular purpose and non-infringement.

12. Limitation of liability

To the maximum extent permitted by law, Pengu is not liable for indirect, incidental, special or consequential damages (lost profits, lost data, lost opportunities). Pengu's total liability to you, in any circumstance, will not exceed the amount you paid Pengu in the 12 months preceding the event giving rise to the claim — or zero if you have never paid. These limits do not apply to liability that cannot be excluded by law.

13. Indemnity

You agree to indemnify Pengu against reasonable losses and costs arising from your breach of these terms or your unlawful use of the Service.

14. Additional terms for apps downloaded from the Apple App Store

When you download a Pengu app from the App Store, the following additional terms apply:

This agreement is between you and Pengu, not with Apple. Apple is not responsible for the app or its content.
The licence is limited to use on Apple-branded devices you own or control, as permitted by the Usage Rules in the App Store Terms of Service.
Apple has no obligation to furnish any maintenance or support services for the app.
If the app fails to conform to any applicable warranty, you may notify Apple and Apple will refund the purchase price (if any); beyond that, Apple has no other warranty obligation whatsoever.
Apple is not responsible for addressing any claims by you or a third party relating to the app, including product liability claims, claims that the app fails to conform to legal or regulatory requirements, and claims under consumer protection law.
If a third party claims the app infringes their intellectual property rights, Pengu — not Apple — is solely responsible for the investigation, defence, settlement and discharge of that claim.
You represent that you are not located in a country subject to a U.S. Government embargo and are not on any U.S. Government list of prohibited or restricted parties.
Apple and its subsidiaries are third-party beneficiaries of these terms and have the right to enforce them against you.

15. Additional terms for apps downloaded from Google Play

Your download and use of the app is also subject to the Google Play Terms of Service. Google is not a party to this agreement and is not responsible for the app. Refund requests for Google Play transactions are handled under Google Play's policies.

16. Governing law and disputes

These terms are governed by the laws of Vietnam. We prefer to resolve disputes amicably — write to hotro@tiengtrungapp.com first. If no agreement is reached within 30 days, the dispute will be submitted to the competent courts of Vietnam. If you are a consumer resident outside Vietnam, this section does not deprive you of rights that the mandatory law of your country of residence grants you.

17. Changes to these terms

If we make significant changes we will update the date at the top of this page and notify you in the app before they take effect. Continuing to use the Service after that date means you accept the new version. If you disagree, you may stop using the Service and delete your account.

18. General

If any provision is held invalid, the remaining provisions stay in force.
Not enforcing a right immediately does not waive it.
You may not assign your rights or obligations under these terms without Pengu's consent.
These terms together with the Privacy Policy constitute the entire agreement between you and Pengu regarding the Service.

19. Contact

Questions about these terms: hotro@tiengtrungapp.com or the contact page.