Privacy Policy

1. Overview and Scope

LingViet LLC (“we,” “us,” “our”) operates the website and web application accessible at lingviet.com (collectively, the “Service”). This Privacy Policy explains what personal information we collect, how we use and share it, how long we retain it, and the rights you have regarding it.

This policy applies to all users of the Service, regardless of location. Additional rights may apply to you based on where you reside — see Section 11 (California/CCPA), Section 12 (EU/GDPR), and Section 9 (Children/COPPA).

By using the Service, you agree to the collection and use of information as described in this policy.

2. Information We Collect

Information you provide directly

• Name and email address (at account creation)
• Profile information: display name, native language, learning goal
• Payment information submitted at checkout (processed by Stripe — see Section 5)
• Communications you send to us (support emails, feedback)

Information generated by your use of the Service

• Study session data: answers, scores, session timing, activity completion
• Vocabulary cards: words saved, SM-2 review state, review history
• Learning path, level, XP, and streak data
• Onboarding selections and preference settings

Information collected automatically

• IP address, browser type and version, operating system
• Referring URLs and pages visited within the Service
• Access timestamps and session duration
• Error logs and performance data

Information stored locally on your device

In-progress session drafts are stored in your browser's localStorage under the key sessionDraft. This data contains your in-progress answers, hints, and session metadata. It is stored exclusively on your device and is never transmitted to our servers unless and until you complete a session. Clearing your browser's localStorage will delete this data permanently.

Authentication data

If you sign in via an OAuth provider (e.g., Google), we receive your name, email address, and OAuth token from that provider, subject to their privacy policy.

3. How We Use Your Information

We use your information for the following purposes:

We do not sell your personal information to third parties. We do not use your personal information for advertising or ad targeting. We do not use your data to train AI models (see Section 5).

Marketing communications

If you have opted in to marketing emails, we may send you product updates, feature announcements, and promotional offers. You may unsubscribe at any time via the link in any marketing email or by contacting lingviet.support@gmail.com. Unsubscribing from marketing does not affect transactional communications.

4. Cookies and Local Storage

Session cookies: We use strictly necessary session cookies to keep you authenticated. These are set by our authentication system and expire when you log out or your session ends.

Functional cookies: We may use cookies to remember your preferences (e.g., theme, language settings).

Analytics: We may use privacy-respecting analytics tools (such as Vercel Analytics) to collect aggregated, anonymized usage data. These tools do not set third-party tracking cookies and do not identify individual users.

No advertising or tracking cookies: We do not use cookies for advertising, behavioral tracking, or cross-site tracking.

Managing cookies: You can control cookies through your browser settings. Disabling strictly necessary cookies will prevent you from logging in. Disabling other cookies may affect functionality.

Do Not Track: LingViet does not currently respond to browser Do Not Track (DNT) signals because no universal standard for DNT compliance exists. We will update this policy if our practices change.

5. Third-Party Services

We share data with the following third-party services to operate the Service. Each has its own privacy policy:

We will update this table as our third-party relationships change.

6. Data Retention

After account deletion, we may retain de-identified, aggregated data that cannot be linked back to you indefinitely for analytics and platform improvement purposes.

7. Data Security

We implement reasonable technical and organizational security measures, including:

• HTTPS/TLS encryption for all data in transit
• Access controls and authentication on our database
• Regular dependency and security updates

No method of transmission over the internet or electronic storage is 100% secure. While we strive to protect your data, we cannot guarantee absolute security.

Data Breach Notification: In the event of a security breach involving your personal information, we will notify affected users and relevant authorities as required by applicable law, including Idaho Code § 28-51-104 (Idaho's data breach notification statute), which requires notification in the most expedient time possible following discovery of a qualifying breach.

8. Your Rights — All Users

Regardless of your location, you may:

• Access: Request a copy of the personal information we hold about you.
• Correction: Correct inaccurate or incomplete data via your profile settings or by contacting us.
• Deletion: Request deletion of your account and associated personal data.
• Data Portability: Request your personal data in a structured, machine-readable format (e.g., JSON or CSV).
• Withdraw Consent: Where processing is based on consent, withdraw that consent at any time without affecting the lawfulness of prior processing.

How to submit a request: Email lingviet.support@gmail.com with the subject line “Privacy Request” and include: your full name, the email address associated with your account, and a description of your request.

Identity verification: To protect your privacy, we will verify your identity before processing any request. Verification typically requires confirming access to your registered email address. We may request additional information if necessary.

Response time: We will respond to verifiable requests within 45 days of receipt. If additional time is required (up to 90 days total), we will notify you of the extension and the reason within the initial 45-day period.

Right to appeal: If we deny your request, you may appeal by replying to our denial notice. We will review the appeal and respond within 30 days.

9. Children's Privacy (COPPA)

LingViet is not directed to children under the age of 13, and we do not knowingly collect personal information from children under 13 without verifiable parental consent, as required by the Children's Online Privacy Protection Act (COPPA).

If you believe a child under 13 has created an account or provided personal information without parental consent, please contact us immediately at lingviet.support@gmail.com with the subject line “COPPA — Child Account.” We will investigate and delete the information within 72 hours of confirming the report.

10. International Users

LingViet LLC is based in Idaho, USA. If you access the Service from outside the United States, your data will be transferred to and processed in the United States, which may have different data protection laws than your country.

By using the Service, you consent to this transfer. We take appropriate steps to ensure that your data receives a level of protection consistent with this policy regardless of where it is processed.

11. California Residents (CCPA / CPRA)

If you are a California resident, you have the following rights under the California Consumer Privacy Act (CCPA) and California Privacy Rights Act (CPRA):

• Right to Know: Request disclosure of the categories and specific pieces of personal information we have collected about you, the sources, the purposes, and the third parties with whom we share it.
• Right to Delete: Request deletion of your personal information, subject to certain exceptions.
• Right to Correct: Request correction of inaccurate personal information.
• Right to Data Portability: Receive your personal information in a portable format.
• Right to Opt Out of Sale: We do not sell personal information. We do not share personal information for cross-context behavioral advertising.
• Right to Non-Discrimination: We will not discriminate against you for exercising any of your CCPA rights. We will not deny you goods or services, charge you different prices, or provide a different level of service because you exercised a privacy right.
• Right to Limit Sensitive Personal Information: We do not use or disclose sensitive personal information beyond what is necessary to provide the Service.

To exercise your California rights, email lingviet.support@gmail.com with subject line “California Privacy Request.” We will respond within 45 days as described in Section 8.

12. EU/EEA and UK Residents (GDPR / UK GDPR)

If you are located in the European Economic Area (EEA) or United Kingdom, you have rights under the General Data Protection Regulation (GDPR) or UK GDPR, including:

• Right of Access (Article 15)
• Right to Rectification (Article 16)
• Right to Erasure (Article 17)
• Right to Restriction of Processing (Article 18)
• Right to Data Portability (Article 20)
• Right to Object (Article 21) — including to processing based on legitimate interests
• Rights related to automated decision-making (Article 22) — we do not make solely automated decisions with legal or similarly significant effects

Legal basis for processing: As detailed in Section 3, we process your data on the basis of contract performance, legitimate interests, and legal obligation. Where we rely on legitimate interests, you have the right to object.

Data transfers: Your data is processed in the United States. We rely on Standard Contractual Clauses (SCCs) or other appropriate safeguards for transfers from the EEA/UK to the US where required.

Complaints: You have the right to lodge a complaint with your local supervisory authority (e.g., your country's data protection authority).

Contact for GDPR inquiries: lingviet.support@gmail.com

13. CAN-SPAM and Email Communications

We comply with the CAN-SPAM Act. Our commercial emails will:

• Clearly identify LingViet LLC as the sender
• Include our contact information: LingViet LLC, Idaho, USA / lingviet.support@gmail.com
• Include a functional unsubscribe link in every marketing email
• Honor unsubscribe requests promptly (within 10 business days)

You may opt out of marketing emails at any time. Opting out does not affect transactional emails (billing receipts, account notices, security alerts).

14. Changes to This Policy

We may update this Privacy Policy from time to time. “Material changes” means changes that reduce your rights, expand the categories of data we collect or share, or significantly alter how we use your information.

For material changes, we will notify you via email and an in-app notice at least 30 days before the change takes effect. For non-material changes, the updated policy will be posted with a new “Last Updated” date. Continued use of the Service after changes take effect constitutes acceptance of the revised policy.

15. Contact

For privacy-related questions, requests, or complaints:

Email: lingviet.support@gmail.com
Subject line: “Privacy Request” or “GDPR Request” as applicable
Entity: LingViet LLC — Idaho, USA

We aim to respond to all inquiries within 5 business days.