Privacy Policy
1. Who we are
Lingua is an AI-assisted English-learning app for Android, published by EXO Studio, Hanoi, Vietnam ("we", "us", "our"). This policy explains what information Lingua handles and how. For any privacy question, contact us at exostudio.feedback@gmail.com.
2. Information we collect
Lingua does not require you to create an account or sign in, and does not ask for your name, email, phone number or other contact details to use the app. The information involved falls into these categories:
| Category | Examples | Where it lives |
|---|---|---|
| Learning content you provide | Text you type in the AI Conversation, "Check my English", vocabulary and grammar features; your conversation history within a session. | Stored on your device; sent to our backend and AI provider only when you use an AI feature. |
| Learning preferences | Your English level, native language, learning goals, interests and correction style. | Stored on your device; included with AI requests to tailor responses. |
| Speech input | What you say during speaking practice. | Processed by your device's speech-recognition service; Lingua receives only the recognized text. Lingua does not record, store or upload audio. |
| Progress & app data | Streaks, XP, daily goals, saved lessons and words, quiz results, reminder settings. | Stored only on your device (local database and preferences). |
| Device & advertising identifiers | Google Advertising ID (or App Set ID), Firebase installation ID, AppMetrica device ID, IP address, device model, OS version, language, country. | Collected by the ad, analytics and attribution SDKs listed in section 5 and sent to those providers. |
| App activity & diagnostics | Screens opened, feature usage, session length, ad impressions and clicks, app version, crash logs and performance data. | Sent to Firebase (Analytics, Crashlytics), AppMetrica, Meta and TikTok. |
| Install & campaign information | How you found and installed Lingua (for example, the ad campaign or install referrer). | Sent to AppMetrica, Meta and TikTok for install attribution. |
| Consent choices | Your ad-consent decision in the EEA, UK and Switzerland. | Stored on your device by Google's User Messaging Platform and passed to ad partners. |
| Purchases (if offered) | Whether you bought an in-app item such as ad removal. | Handled by Google Play Billing; we do not receive your payment card details. |
Lingua does not collect your precise location, contacts, photos or files, and does not record or upload audio.
3. How we process information
Most of Lingua works entirely on your device. On-device processing includes text-to-speech pronunciation, speech recognition (via your device's system service), the built-in offline grammar lessons, and all storage of your progress, saved content and preferences.
When you use an AI feature, Lingua sends your typed text together with your learning preferences (level, native language, goals, interests, correction style) and the current conversation context to our backend over an encrypted (HTTPS) connection. Our backend forwards the request to an AI language-model provider to generate the reply, then returns it to the app. Your name is not included in these requests.
While you use Lingua, the third-party SDKs listed in section 5 automatically collect device identifiers, app activity, ad interactions and diagnostics as described above and send them to their providers. Google AdMob uses this information to select, show and measure ads. Firebase Remote Config is used to adjust app settings (for example, ad frequency) remotely, and Firebase Cloud Messaging may deliver notifications.
4. Purposes and legal bases
- Provide the learning features — generating AI conversations, corrections, explanations, vocabulary and quizzes, and saving your progress on your device. This is necessary to deliver the service you request (performance of a contract) and our legitimate interest in operating the app.
- Local reminders — showing the daily practice notification you enable, based on your consent (which you can withdraw at any time in the app).
- Show ads that keep Lingua free — serving, limiting and measuring ads through Google AdMob and its mediation partners. Personalised ads in the EEA, UK and Switzerland are shown only with your consent; elsewhere they rely on our legitimate interest and you can opt out in your device settings (see section 11).
- Analytics, diagnostics and app configuration — understanding how features are used, fixing crashes and tuning settings, based on our legitimate interest in improving the app (or your consent where required).
- Install attribution — measuring which marketing campaigns lead to installs, based on our legitimate interest (or your consent where required).
5. Service providers
We rely on the following providers:
- Our AI backend (operated by EXO Studio) — receives your AI requests and manages access to the language model.
- AI language-model provider — accessed by our backend through the OpenCode API to generate responses to your requests.
- Google AdMob (Google LLC) and its mediation partners (such as Unity Ads, ironSource, InMobi, Chartboost, Liftoff/Vungle, Mintegral and Pangle) — advertising. How Google uses data.
- Google User Messaging Platform — collecting and storing ad-consent choices in the EEA, UK and Switzerland.
- Google Firebase (Analytics, Crashlytics, Remote Config, Cloud Messaging) — analytics, crash reporting, app configuration and notifications. Firebase privacy.
- AppMetrica (YANDEX LLC) — analytics and install attribution. AppMetrica terms.
- Meta Platforms (Facebook SDK) — app event measurement and install attribution for our ads on Meta. Meta Privacy Policy.
- TikTok (TikTok Business SDK) — app event measurement and install attribution for our ads on TikTok. TikTok privacy.
- Google Play — app distribution, in-app purchases (if offered) and install referrer.
Speech recognition and text-to-speech are performed by the service built into your Android device (for example, the provider you have configured in your system settings). That processing is governed by that provider's and your device manufacturer's privacy terms.
6. Sharing and sale of data
We do not sell your information for money. We share information only with the providers listed in section 5: the content of your AI requests goes to our AI backend and language-model provider, and device identifiers, app activity and ad interactions are collected by the advertising, analytics and attribution SDKs. Under some US state laws, allowing ad partners to use identifiers for personalised advertising may be considered a "sale" or "sharing" of personal information; you can opt out as described in section 11. We may disclose information if required by law.
7. Data retention
Data stored on your device (progress, saved words and lessons, preferences, conversation history) remains until you delete it in the app or uninstall Lingua. AI requests are transmitted to produce a response and are not tied to an account or to your identity, because Lingua does not maintain user accounts or profiles. Data collected by the third-party SDKs is retained by those providers according to their own policies (for example, Firebase Analytics data is kept for up to 14 months under our settings). If your device backup is enabled, your on-device data may be included in your own device backup.
8. Security
- All network requests use encrypted HTTPS. Plain-text connections are permitted only for local development hosts and are never used in the released app.
- The app never contains AI provider keys; those exist only in our backend environment.
- Your learning data is stored in the app's private storage on your device.
No method of transmission or storage is completely secure, but we take reasonable measures to protect your information.
9. Device permissions
Lingua requests only the permissions its features need:
| Permission | Why it is used |
|---|---|
| Microphone (record audio) | Speaking practice, so your device's speech recognizer can convert your speech to text. Audio is not stored or uploaded by Lingua. |
| Internet & network state | Sending AI requests and detecting whether you are online. |
| Notifications | Showing the daily practice reminder you choose to enable. |
| Run at startup | Re-scheduling your daily reminder after the device restarts. |
You can change or revoke permissions at any time in your Android system settings. Denying microphone access simply disables speaking practice.
10. Children's privacy
Lingua is a general-audience learning app and is not directed to children under 13 (or the minimum age required in your country). We do not knowingly collect personal information from children. If you believe a child has provided personal information, contact us and we will address it.
11. Your rights (GDPR & CCPA)
Because Lingua has no accounts, most of your data stays under your direct control on your device. Depending on where you live, you may have rights to access, correct, delete or restrict processing of your personal information, and (under the CCPA/CPRA) to know what is collected and to opt out of its sale — note that we do not sell personal information.
- Access & deletion on-device: you can view and delete your saved words, lessons, conversations and progress within the app, or remove all of it by uninstalling Lingua.
- Requests to us: to exercise any right, email exostudio.feedback@gmail.com. We will respond as required by applicable law and will not discriminate against you for exercising your rights.
- Ad consent (EEA, UK, Switzerland): when you first open Lingua you can consent to, or manage, personalised ads. You can change your choice later from the privacy options in the app where available, or by clearing the app's data.
- Advertising ID controls: on Android you can reset or delete your advertising ID, or opt out of personalised ads, under Settings › Google › Ads (or Settings › Privacy › Ads). This also serves as your opt-out of "sale"/"sharing" under US state laws.
12. International transfers
Our backend, the AI provider and the advertising, analytics and attribution providers listed in section 5 may process information on servers located outside your country, including outside the European Economic Area. Where required, we rely on appropriate safeguards for such transfers, such as the European Commission's Standard Contractual Clauses.
13. Changes to this policy
We may update this policy as the app evolves. We will revise the "Last updated" date above and, for material changes, provide notice within the app or store listing. Continued use of Lingua after an update means you accept the revised policy.
14. Contact
EXO Studio, Hanoi, Vietnam
Email: exostudio.feedback@gmail.com