Privacy Policy

1 Information We Collect

We collect the following information only as needed to provide the App.

• • Email address: collected when you sign in with Apple ID or Google. Used for account identification and authentication.
• • User ID: a unique identifier issued by Firebase Authentication. Used to associate your learning data with your account, and to analyze how the App is used.
• • Approximate location: the country, region, and city inferred from your IP address, used for usage analytics.
• • Purchase history: to manage your subscription, RevenueCat processes information such as purchase status and expiration. Payment details such as credit card numbers are processed by Apple App Store or Google Play, and we do not receive them directly.
• • Product activity (learning data): answers, correctness, learning progress, review list, completion timestamps, etc. — data needed to provide the App and support continued learning — as well as usage such as screens viewed and time spent.
• • English text you enter or speak (when using AI features): to provide AI feedback, AI conversation, and pronunciation feedback, the English text you enter or speak (composition/rearrangement answers, conversation messages, etc.) is sent to Anthropic and Google, which provide the AI services. This is sent only when you use these features and is used solely to provide them. Before you first use an AI feature, we disclose what data is sent and to whom inside the app and obtain your consent before sending (you can withdraw it anytime in Settings).
• • Voice data: only when you use the pronunciation practice feature, your recorded audio is sent to Microsoft's speech analysis service (consent obtained in-app before sending). It is not stored on our servers. Voice input for question answers and for AI conversation is transcribed by Apple's speech recognition service on iOS (this includes server-side processing), and on Android by the speech recognition service built into your device's operating system (provided by Google on most devices; this may include server-side processing). Only when no speech recognition service is available on an Android device, voice input for AI conversation is sent to OpenAI's speech recognition service for transcription.
• • Inquiry content: the name, email address, subject, and message you submit through the contact form on this website. We also collect technical information such as your IP address and User-Agent to prevent abuse. We use these solely to respond to your inquiry and to send the automatic acknowledgement email.

* We do not collect addresses, phone numbers, dates of birth, or advertising identifiers such as IDFA, and we do not perform tracking. We collect your name when you use the contact form on this website. Using the App itself never requires your name.

2 Purpose of Use

We use collected information only for the following purposes.

• •Providing the App's features and managing learning progress
• •Providing learning support features such as AI feedback and pronunciation feedback
• •Managing subscriptions and verifying validity
• •Responding to user support inquiries and sending notifications
• •Ensuring service security and preventing abuse
• •Maintaining and improving the service, and announcing new features

3 Third-Party Services (Processors)

We use third-party services to deliver our features. The main services we currently use are listed below; they may change as we improve the product or change our infrastructure. Please also review each service's privacy policy.

• •Google (Firebase): authentication, database (Firestore), audio file delivery (Cloud Storage), usage analytics (Google Analytics)
• •RevenueCat: subscription state management
• •Apple: speech recognition on iOS (question answers and AI conversation voice input; includes server-side processing), Sign in with Apple
• •The speech recognition service built into your device's operating system (Android): transcription of voice input for question answers and AI conversation. The provider differs by device (Google on most devices). Depending on the device and its settings, audio is sent to that provider's servers for recognition.
• •Anthropic: AI feedback (composition/rearrangement), AI conversation responses and grading, pronunciation feedback generation. Receives the English text you enter or speak.
• •Google: AI conversation response generation. Receives your conversation messages.
• •Microsoft: pronunciation analysis (sending recorded audio), AI conversation speech synthesis
• •OpenAI: fallback speech synthesis for AI conversation, and fallback speech recognition (when no speech recognition service is available on an Android device)
• •Studyplus (Studyplus Inc.): study-record integration. Only if you enable the integration, the length of time you studied and the date and time are sent to Studyplus (your answers and the text you enter are not sent). You can unlink at any time from Settings.
• •Cloudflare: hosting of this website and bot protection for the contact form
• •Resend: sending email from the contact form (notification to us and the automatic acknowledgement to you)

When we share data with the third parties above, we confirm through their privacy policies and data processing terms that they protect the data to a standard equal to or stronger than this policy. Data sent to AI services (Anthropic, Google, OpenAI) is processed under their respective policies solely to provide the relevant feature.

4 International Transfers

Some of the third-party services above operate on servers in the United States and other countries, and your information may be transferred there. We confirm the data protection level at the destination and apply appropriate safeguards before such transfers. By using the App, you are deemed to consent to these transfers.

5 Security Measures

We implement appropriate organizational, personnel, and technical measures to prevent leakage, loss, or damage of personal information. Learning data and account information are transmitted over encrypted communications (HTTPS) and stored securely in the cloud.

6 Disclosure to Third Parties

We do not provide personal information to third parties without your prior consent, except as permitted by law or in the case of the processors described above. We never sell personal information.

7 Data Retention, User Rights & Account Deletion

We keep your account details and learning data for as long as your account exists, and we delete the associated data when you delete your account. We keep inquiry content for as long as we need it to respond and to prevent abuse. The English text and audio sent to provide the AI features are not stored on our servers (how the receiving services handle them is governed by their own policies). Where the law requires us to retain information, we keep it for the period the law requires.

You have the following rights:

• •Request disclosure, correction, deletion, or suspension of use of your personal information
• •Immediately delete your account and related data via "My Page → Delete Account" in the App
• •Opt out of notifications and data collection

For requests that cannot be handled in-app, please contact us at the address in the last section after identity verification.

8 Children's Privacy

The App is not intended for children under 13. If a user under 13 wishes to use it, please do so under the consent and supervision of a guardian. If we discover that we have unintentionally collected personal information from a child under 13, we will delete it promptly.

9 Policy Changes

We may update this policy as needed. For significant changes, we will notify users through in-app notices or on the website.

10 Contact

For inquiries about the handling of personal information, please contact: