Privacy Policy
Effective Date: January 19, 2026
Last Updated: January 19, 2026
Lang Shadow Development Team ("we," "our," or "us") is committed to protecting your privacy. This Privacy Policy explains how we collect, use, disclose, and safeguard your information when you use our mobile application Lang Shadow (the "App") available on iOS (Apple App Store) and Android (Google Play Store).
By using the App, you agree to the collection and use of information in accordance with this Privacy Policy. If you do not agree with this policy, please do not use the App.
Age Restriction: Lang Shadow is intended for users aged 13 and older. We do not knowingly collect personal information from children under 13. If we discover that a child under 13 has provided us with personal information, we will delete such information immediately.
1. Information We Collect
1.1 Personal Information You Provide
When you create an account or use our App, we collect the following information:
- Account Information: Email address, name, and profile picture (if you sign in via Google or Apple)
- Authentication Data: Firebase authentication tokens for secure login
- Learning Preferences: Mother tongue language, target learning languages, and timezone settings
- Profile Data: Avatar URL and display name
1.2 Learning Activity Data
To provide personalized learning experiences, we collect:
- Video Interactions: Videos you watch, save, and bookmark
- Vocabulary Learning: Words and phrases you study, translations you request, and vocabulary saved for review
- Transcript Data: Video transcripts you save and translate for language learning
- Speech Practice: Audio recordings of your pronunciation practice and speaking exercises (processed for feedback only, not permanently stored)
- Conversation History: AI-powered conversation practice sessions for language improvement
- Learning Progress: Your learning statistics, daily usage, and progress tracking data
- Search History: Keywords and phrases you search within the App
1.3 Subscription and Payment Information
For premium subscriptions, we collect:
- Payment Transactions: Transaction IDs from Apple App Store or Google Play Store
- Subscription Status: Active subscriptions, renewal dates, and subscription history
- Device Information: Device identifiers for subscription validation (limited to 3 devices per user)
- Purchase Details: Package purchased, pricing, and currency
Important Payment Information:
- We do NOT collect or store your credit card information
- All payment processing is handled securely by Apple App Store and Google Play Store
- To Cancel Subscription:
- iOS: Go to Settings → [Your Name] → Subscriptions → Lang Shadow → Cancel Subscription
- Android: Open Google Play Store → Menu → Subscriptions → Lang Shadow → Cancel Subscription
- Refunds: Managed by Apple or Google according to their refund policies. Contact Apple/Google support for refund requests
- Deleting the app does NOT cancel your subscription. You must cancel through your Apple/Google account
1.4 Device Permissions
Lang Shadow requires the following device permissions to function properly:
- Microphone Access: Required for speech practice, pronunciation checking, and voice recording features. Audio is processed in real-time and NOT permanently stored on our servers. You can deny this permission, but speech-related features will be unavailable.
- Network Access: Required to download videos, sync learning progress, and access AI-powered features
1.5 Technical and Usage Information
- Device Information: Device model, operating system version, and unique device identifiers
- App Usage Data: Features accessed, time spent on activities, and usage patterns
- Error Logs: Technical logs to diagnose and fix app issues
1.6 Information We Do NOT Collect
We want to be transparent about what we don't collect:
- No Location Tracking: We do not collect your precise location data
- No Analytics Tools: We do not use Google Analytics, Firebase Analytics, or any third-party analytics services
- No Advertising Networks: We do not use advertising networks or ad tracking
- No Persistent Audio Storage: Speech recordings are processed in real-time for pronunciation feedback and are not permanently stored
- No Contacts or Photos: We do not access your contacts, photo library, or camera
- No Background Location: We do not track your location in the background
Important: We will NEVER sell, rent, or trade your personal information to third parties for marketing purposes. Your data is used solely to provide and improve Lang Shadow's language learning services.
2. How We Use Your Information
We use the collected information for the following purposes:
2.1 To Provide and Improve Our Services
- Create and manage your user account
- Authenticate your identity through Firebase (Google or Apple Sign-In)
- Deliver personalized language learning content and recommendations
- Track your learning progress and provide statistics
- Enable vocabulary saving, translation features, and transcript access
- Provide AI-powered conversation practice and pronunciation feedback
2.2 To Process Subscriptions and Payments
- Process and validate subscription purchases through Apple or Google
- Manage subscription renewals, cancellations, and refunds
- Verify subscription status and enforce usage limits for free and premium users
- Handle webhook notifications from Apple and Google for subscription events
2.3 To Communicate With You
- Send important updates about your account or subscription
- Respond to your inquiries and provide customer support
- Notify you of changes to our services or policies
2.4 To Enhance App Security and Functionality
- Prevent fraud and unauthorized access to your account
- Debug technical issues and improve app performance
- Enforce our Terms of Service and prevent abuse
3. Third-Party Services We Use
Lang Shadow uses the following third-party services to provide functionality:
3.1 Authentication Services
3.2 AI and Translation Services
3.3 Text-to-Speech Services
3.4 Payment Processing
3.5 Cloud Hosting
- Cloud Infrastructure Provider: Our backend services are hosted on cloud servers. Your data is stored securely on servers located in compliance with international data protection standards.
Important Notes:
- These third-party services have their own privacy policies. We recommend reviewing them to understand how they handle your data.
- Data Minimization: We only share the minimum data necessary for each service to function (e.g., text for translation, audio for speech processing).
- No Personal Data Sharing: We do NOT share your email, name, or other personal identifiable information with OpenAI, Azure, or Google Cloud services. Only learning content (text, audio) is sent for processing.
- Temporary Processing: Data sent to AI services is processed in real-time and not stored by these providers for training purposes (per our service agreements).
- Payment Security: All payment information is handled exclusively by Apple and Google. We never have access to your credit card or payment details.
4. Data Sharing and Disclosure
We do not sell, rent, or trade your personal information to third parties. We may share your information only in the following circumstances:
4.1 With Your Consent
We may share your information with third parties when you explicitly consent to such sharing.
4.2 Service Providers
We share data with trusted service providers (listed in Section 3) who perform services on our behalf, such as authentication, AI processing, and text-to-speech generation. These providers are contractually obligated to protect your data and use it only for the purposes we specify.
4.3 Legal Requirements
We may disclose your information if required by law or in response to valid legal requests, such as:
- Complying with court orders or government regulations
- Protecting the rights, property, or safety of Lang Shadow, our users, or the public
- Investigating fraud or security issues
4.4 Business Transfers
If Lang Shadow is involved in a merger, acquisition, or sale of assets, your information may be transferred as part of that transaction. We will notify you via email or app notification before your data is transferred and becomes subject to a different privacy policy.
5. Data Retention
We retain your personal information only as long as necessary to provide our services and fulfill the purposes outlined in this Privacy Policy:
- Active Accounts: Your data is retained while your account is active
- Account Deletion: When you delete your account, we will permanently delete your personal information and learning data within 30 days
- Subscription Records: Payment transaction records may be retained for up to 7 years for legal and accounting compliance
- Backup Data: Deleted data may persist in backup systems for up to 90 days before permanent removal
6. Your Rights and Choices
You have the following rights regarding your personal information:
6.1 Access and Correction
You can access and update your account information directly within the App settings.
6.2 Account Deletion and Data Deletion Request
You have the right to delete your account and all associated data at any time. We provide TWO ways to delete your account:
Option 1: In-App Deletion (Recommended)
- Open the Lang Shadow app
- Go to Settings → Account
- Select "Delete Account"
- Confirm your decision
Option 2: Email Request
If you're unable to access the app, send an email to wisbi.dev@gmail.com with:
- Subject: "Account Deletion Request"
- Your registered email address
- Your full name (as registered in the app)
What happens after deletion:
- Your account will be deactivated immediately
- All personal data and learning history will be permanently deleted within 30 days
- You will receive a confirmation email once deletion is complete
- Active subscriptions will be cancelled (refunds subject to Apple/Google policies)
- Some data may be retained for up to 7 years for legal and accounting compliance (payment transaction records only)
Note: Account deletion is permanent and cannot be undone. All your learning progress, saved videos, and vocabularies will be lost.
6.3 Data Portability
You have the right to request a copy of your personal data in a machine-readable format. Contact us at the email below to make this request.
6.4 Notification Preferences
Push Notifications: Lang Shadow may send you push notifications for:
- Learning reminders and daily practice encouragement
- Subscription status updates and renewal notifications
- Important account or security alerts
You can control notification preferences:
- In the App: Go to Settings → Notifications to customize notification types
- On Your Device: Go to device Settings → Notifications → Lang Shadow to disable all notifications
Note: Disabling notifications will not affect your ability to use the app, but you may miss important updates.
6.5 Withdraw Consent
If you previously consented to data processing, you may withdraw your consent at any time by deleting your account or contacting us.
7. Data Security
We take data security seriously and implement industry-standard security measures to protect your information:
- Encryption: Data transmitted between your device and our servers is encrypted using HTTPS/TLS protocols
- Secure Authentication: Firebase authentication with industry-standard security protocols (OAuth 2.0)
- Access Controls: Strict access controls to limit who can access user data within our organization
- Regular Security Audits: We regularly review and update our security practices
- JWT Token Authentication: Secure token-based authentication for API requests
However, no method of transmission over the internet or electronic storage is 100% secure. While we strive to protect your personal information, we cannot guarantee its absolute security.
7.1 Data Breach Notification
In the unlikely event of a data breach that affects your personal information, we will:
- Notify affected users via email within 72 hours of discovering the breach
- Provide details about what information was compromised
- Explain the steps we're taking to address the breach
- Offer guidance on protecting your account
- Notify relevant authorities as required by law (GDPR, CCPA, etc.)
8. International Data Transfers
Lang Shadow operates globally and is available in all countries. Your information may be transferred to and processed in countries other than your country of residence, including Vietnam and countries where our cloud service providers operate.
By using the App, you consent to the transfer of your information to countries outside your country of residence, which may have different data protection laws. We ensure that appropriate safeguards are in place to protect your data in accordance with this Privacy Policy.
9. Children's Privacy (COPPA Compliance)
Age Restriction: Lang Shadow is intended for users aged 13 years and older. We do not knowingly collect personal information from children under 13 years of age.
For Parents and Guardians:
- If you believe your child under 13 has created an account or provided personal information to Lang Shadow, please contact us immediately at wisbi.dev@gmail.com
- We will promptly investigate and delete any information from children under 13 within 24 hours of verification
- We do not require disclosure of more information than is reasonably necessary to participate in the service
For Teen Users (13-17 years old):
- We recommend reviewing this Privacy Policy with your parent or guardian
- Parents/guardians can request to review, delete, or stop the collection of their teen's information by contacting us
- Teens have the same rights as adult users regarding data access and deletion
Educational Use: If you are a teacher or school administrator interested in using Lang Shadow for students under 13, please contact us to discuss appropriate safeguards and parental consent procedures.
10. California Privacy Rights (CCPA)
If you are a California resident, you have additional rights under the California Consumer Privacy Act (CCPA):
- Right to Know: You can request information about the personal data we collect, use, and disclose
- Right to Delete: You can request deletion of your personal information
- Right to Opt-Out: You have the right to opt out of the sale of personal information (Note: We do not sell personal information)
- Right to Non-Discrimination: We will not discriminate against you for exercising your CCPA rights
To exercise these rights, please contact us using the information provided in Section 13.
11. European Privacy Rights (GDPR)
If you are located in the European Economic Area (EEA) or the United Kingdom, you have additional rights under the General Data Protection Regulation (GDPR):
- Right to Access: Request access to your personal data
- Right to Rectification: Request correction of inaccurate data
- Right to Erasure: Request deletion of your data ("right to be forgotten")
- Right to Restrict Processing: Request limitation of how we process your data
- Right to Data Portability: Receive your data in a structured, machine-readable format
- Right to Object: Object to certain types of processing
- Right to Withdraw Consent: Withdraw consent for data processing at any time
To exercise these rights, please contact us using the information in Section 13. You also have the right to lodge a complaint with a supervisory authority in your jurisdiction.
12. Changes to This Privacy Policy
We may update this Privacy Policy from time to time to reflect changes in our practices, legal requirements, or for other operational reasons. When we make material changes, we will:
- Update the "Last Updated" date at the top of this policy
- Notify you via email or in-app notification
- Request your consent if required by applicable law
We encourage you to review this Privacy Policy periodically to stay informed about how we protect your information.
13. Contact Us
14. Acceptance of This Policy
By using Lang Shadow, you acknowledge that you have read and understood this Privacy Policy and agree to its terms. If you do not agree with this policy, please do not use the App.
© 2026 Lang Shadow Development Team. All rights reserved.