Privacy Policy

This Privacy Policy explains how Wisbi Vietnam ("we," "our," or "us") collects, uses, shares, stores and deletes information when you use the mobile app Lang Shadow: English Shadowing (the "App"), available on Google Play and the Apple App Store, and our website langshadow.com.

1. Information We Collect

1.1 Account information

You sign in with Google or Apple. When you do, we receive and store:

• Your email address
• Your name and profile picture, if your Google or Apple account provides them
• A user ID from Firebase Authentication

If you use Sign in with Apple and choose to hide your email, we only receive Apple's relay address.

1.2 Profile and learning preferences

• Your English level, learning goals and the topics you choose during setup
• Your native language, if you tell us, so we can show translations
• Your time zone, so streaks and daily limits reset at the right time
• The scoring accent you pick (US, UK or Australian)

1.3 Learning activity

• Videos, podcasts and channels you watch, save or follow
• Words, phrases and sentences you save to your Notebook, and the translations you request
• Pronunciation scores, including per-word and per-sound results
• Your messages in AI role-play and "How to Talk" conversations
• Game results, streaks, XP, quests and league standings
• Search keywords you type in the App

1.4 Voice recordings

When you tap the microphone to practise, the App records your voice and sends the audio to our server, which passes it to Microsoft Azure Speech for pronunciation scoring and transcription. We use the audio only to give you a score and feedback.

• On our servers: audio is processed in memory and is not saved. We keep the resulting scores and text, not the audio.
• On your device: the "My voice" feature keeps your latest recordings on your phone so you can play them back. They stay on your device and are removed when you uninstall the App.
• Voice typing: some text fields let you dictate. This uses your phone's built-in speech recognition (Google on Android, Apple on iOS) under their own privacy terms.

1.5 Purchases

• Purchase tokens and transaction IDs from Google Play or the App Store
• Which plan you bought, its status, renewal and expiry dates

Payments are processed entirely by Google or Apple. We never see or store your card or other payment details.

1.6 Device, usage and diagnostic data

• Device model, operating system and version, app version, language and approximate country
• An installation ID and a push notification token
• Which screens and features you use and for how long (app analytics)
• Crash reports and error logs

1.7 What we do not collect

• We do not collect your precise or approximate location from GPS
• We do not access your contacts or photo library
• We do not show ads and do not collect the Android advertising ID or the iOS IDFA
• The camera is used only if you choose to record a video of yourself while reading. That video stays on your device and is never uploaded

2. App Permissions

• Microphone: to record your voice for pronunciation practice. Optional — without it, speaking features are unavailable.
• Notifications: to send practice reminders and review prompts. Optional — you can turn them off in your phone's settings at any time.
• Camera: only for the optional self-recording feature described above.
• Internet, foreground media playback and keep-awake: to stream lessons and keep audio playing while you practise.

3. How We Use Your Information

• To create your account and sign you in
• To provide lessons, pronunciation scoring, translations and AI conversation practice
• To recommend content at your level and track your progress
• To verify purchases and apply free and paid usage limits
• To send practice reminders and review notifications
• To find and fix crashes and errors, prevent abuse, and keep the service secure
• To understand which features are used so we can improve the App
• To reply to you when you contact support

We do not sell your personal information, and we do not use it for advertising or share it with data brokers.

4. Third-Party Services That Process Your Data

We use the following service providers. Each receives only the data it needs for the purpose listed, and processes it on our behalf under its own terms.

• Google Firebase Authentication — sign-in with Google or Apple (email, name, user ID). Privacy
• Google Analytics for Firebase — app usage analytics (app events, our internal user ID, installation ID, device and OS, approximate country, English level and native language). Privacy
• Firebase Crashlytics — crash reports (stack traces, device state, our internal user ID). Privacy
• Firebase Cloud Messaging — delivering push notifications (push token). Privacy
• Microsoft Azure AI Speech — pronunciation scoring, speech-to-text and text-to-speech (your voice recordings and the practice text). Privacy
• Google Cloud Text-to-Speech — generating spoken audio from lesson text. Privacy
• OpenAI API — translations, vocabulary explanations and AI conversation replies (the text you type or say in those features). Privacy
• Google Gemini API — AI tutor and role-play replies (the text of your conversation). Privacy
• YouTube — lesson videos are played through the embedded YouTube player, so YouTube may collect data under its own terms. Privacy
• Google Play Billing and Apple In-App Purchase — subscriptions and payments. Google · Apple
• Server hosting provider — stores our database and runs our backend.

We do not send your name or email address to the AI and speech providers — only the text or audio needed for the request.

5. Sharing and Disclosure

We share personal information only:

• With the service providers listed in Section 4, to run the App
• With other users, in a limited way: your display name, avatar, XP and league rank appear on leaderboards
• When required by law, a court order, or to protect the safety of users or the public
• As part of a merger or sale of the business, in which case we will notify you before your data becomes subject to a different policy

6. Data Security

• All data between the App and our servers is encrypted in transit with HTTPS (TLS)
• Access to our API requires a signed token tied to your account
• Access to the database is limited to the people who operate the service

No system is perfectly secure, but we work to protect your information and fix issues quickly.

7. Data Retention and Deletion

• We keep your account and learning data for as long as your account is active
• When you delete your account, access ends immediately and your personal and learning data is permanently deleted within 30 days
• Purchase records may be kept for up to 7 years where tax or accounting law requires it. They contain purchase details only, not your learning content
• Server backups that contain deleted data are overwritten within 90 days
• Analytics and crash data are kept by Firebase according to its retention settings, then removed

How to delete your account

1. Open the App and go to the Profile tab
2. Tap the ⋮ menu in the top-right corner
3. Tap Delete Account, then confirm

If you no longer have the App, follow the steps at langshadow.com/delete-account or email wisbi.dev@gmail.com with the subject "Account Deletion Request" from the address you signed in with.

Deleting your account does not cancel a subscription. Cancel it in Google Play or the App Store.

8. Your Rights and Choices

• Access and correction: view and edit your profile in the App, or ask us for a copy of your data
• Deletion: delete your account as described in Section 7
• Notifications: turn them off in your phone's settings
• Microphone and camera: revoke permission in your phone's settings at any time

Depending on where you live (for example the EEA, UK or California), you may also have the right to restrict or object to processing, to data portability, and to complain to a data protection authority. To use any of these rights, email wisbi.dev@gmail.com. We reply within 30 days.

9. International Transfers

We are based in Vietnam, and our service providers operate in several countries, including the United States. Your information may be processed outside your country, and we rely on our providers' standard safeguards for those transfers.

10. Children

The App is not directed to children under 13, and we do not knowingly collect personal information from them. If you believe a child under 13 has given us personal information, email wisbi.dev@gmail.com and we will delete it.

11. Our Website

Our website langshadow.com uses Google Analytics 4 to count visits (pages viewed, referrer, device type, approximate region) using a cookie. You can block it with your browser settings or the Google Analytics Opt-out Add-on.

12. Changes to This Policy

If we change this policy, we will update the "Last Updated" date above. For significant changes we will also tell you in the App.

13. Contact Us

© 2026 Wisbi Vietnam. All rights reserved.

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