Privacy Policy

Last updated: September 30, 2026

Introduction

We, the LearnThai team, place great importance on user privacy. This privacy policy explains what data LearnThai handles when you use the app to learn Thai vocabulary, where that data is stored, and which third-party services are involved.

1. Data Stored on Your Device

By default, LearnThai works entirely on your device, without an account. The following data is stored locally and never leaves your device unless you use one of the optional features described below:

• Your vocabulary: your decks (name, description) and the words they contain (Thai romanization, Thai script, English translation).
• Your learning progress: for each word, the number of correct and incorrect answers, your mastery level, and the date it was last reviewed, as well as your in-progress study sessions.
• Your settings: study direction, pronunciation (text-to-speech) preference and, if you provide one, your Anthropic API key (see Section 4).

Uninstalling the app deletes all of this local data.

2. Optional Account (Google Sign-In and Sign in with Apple)

You can optionally sign in with your Google account or, on iOS, with Sign in with Apple, through Firebase Authentication (a service provided by Google), to back up your data and restore it on another device. When you sign in, we receive from your chosen provider:

• A unique account identifier (Firebase UID).
• With Google: your email address, and your name and profile picture as provided by your Google account.
• With Apple: your email address and your name, if you choose to share them. Apple lets you hide your real email address using "Hide My Email", in which case we only receive a private relay address.

This information is used only to identify your account and link it to your cloud backup. It is not used for advertising, and it is not sold or shared with anyone else.

3. Cloud Backup

When you are signed in, LearnThai backs up your data to Cloud Firestore (Firebase, provided by Google). Backups run automatically after you make changes, once your device is linked to your account. The backup contains:

• Your decks and the words they contain (Thai romanization, Thai script, English translation).
• Your learning progress for each word (correct and incorrect answer counts, mastery level, date last reviewed).
• A summary of the backup (date of the last backup, number of decks and words).

Your backup is protected by security rules that allow only your own signed-in account to read or write it. Your API key and your app settings are not included in the backup.

Signing out stops automatic backups on that device. Your backup remains stored in the cloud so you can restore it later, until you delete your account (see Section 7).

4. AI Features (Claude by Anthropic)

LearnThai offers two optional features powered by Claude, an AI model provided by Anthropic:

• Automatic translation during CSV import: when an imported word is missing its Thai romanization, Thai script or English translation, the words that need completing are sent to Claude, which fills in the missing values.
• Deck assistant: a chat assistant that helps you reorganize your decks (create, rename, merge, split decks and move words). The messages you write, along with the names of your decks and the words they contain, are sent to Claude so it can make the changes you ask for.

These features only work with your own Anthropic API key, which you enter in the app's settings. Please note:

• Your API key is stored only on your device. It is never sent to us, and it is not included in the cloud backup.
• Requests are sent directly from your device to Anthropic's servers over an encrypted connection; they do not go through any server operated by us.
• This data is processed by Anthropic under your own account and agreement with Anthropic. We encourage you to review Anthropic's Privacy Policy. Any usage costs are billed by Anthropic to your account.
• The assistant's conversation is kept in memory only while you use it and is not saved by the app.

If you do not enter an API key, no data is ever sent to Anthropic.

5. Pronunciation (Text-to-Speech)

Thai pronunciation is played using the text-to-speech engine installed on your device (for example, the one provided by Apple on iOS or by Google on Android). Depending on your device and its settings, this engine may process the text to be spoken according to its provider's own privacy policy. You can turn pronunciation off in the app's settings.

6. Importing and Exporting Files

When you import a CSV file, the app only reads the file you select. When you export your words, a CSV file is created and handed to your device's share sheet; it is only sent where you choose to send it.

7. Data Retention and Deletion

• Local data: you can delete your decks from the app at any time, and uninstalling the app removes all local data, including your API key.
• Cloud backup and account: your backup is kept for as long as your account exists. You can delete your account at any time from the app, in Settings > Delete account. After you confirm your identity by signing in again, this immediately and permanently deletes your cloud backup and your account. If you signed in with Apple, the app's access to your Apple ID is also revoked. The decks stored on your device are kept, so you can continue using the app without an account.

If you can no longer access the app, you can also request the deletion of your account and backup by contacting us at the email address in Section 12 from the email address linked to your account. We will delete them within 30 days.

8. Data Sharing

LearnThai does not sell your data and contains no advertising or analytics tools. Your data is only handled by the following third parties, strictly to provide the app's features:

• Google (Firebase): authentication and cloud backup, only if you sign in.
• Apple: authentication, only if you choose Sign in with Apple.
• Anthropic: AI translation and the deck assistant, only if you enter your own API key and use these features.
• Your device's text-to-speech provider: pronunciation, if enabled.

9. Security

All communication with Firebase and Anthropic uses encrypted connections. Access to your cloud backup is restricted to your own signed-in account by Firebase security rules. No system is perfectly secure, but we take reasonable measures to protect your data.

10. Children's Privacy

LearnThai is not directed at children under 13, and we do not knowingly collect personal data from them. If you believe a child has provided us with personal data, please contact us and we will delete it.

11. Changes to the Privacy Policy

We may update this privacy policy from time to time. We recommend checking this page periodically to stay informed of any changes. The date at the top of this page shows when it was last updated.

12. Contact

If you have any questions or concerns about this privacy policy, or want to delete your data, you can contact us at: bouaoun.bryan@gmail.com