LinguaFlowPrivacy Policy for LinguaFlow
Last updated: 22 October 2026
LinguaFlow ("the app") is a Mandarin Chinese learning app that turns videos you already own into interactive lessons. This policy explains exactly what the app collects, what it does not, and what control you have.
The short version: your videos, audio and transcripts never leave your device. The only things that reach a server are your account email (if you choose to sign in), a single sentence at a time when you explicitly ask for an AI explanation, your subscription status, and a report on a For You clip if you send one.
Who we are
LinguaFlow is developed by I Nyoman Surya Pradipta.
Contact: suryapradipta@icloud.com
We are the data controller for the limited personal data described below.
What stays on your device
The core of LinguaFlow runs entirely offline. The following never leave your device and are never uploaded to us or anyone else:
- Your video files. Imported videos are copied into the app's private storage and stay there.
- Extracted audio. Created locally to run speech recognition, stored locally.
- Transcripts and translations. Produced on-device by Apple's Speech and Translation frameworks.
- Your saved words, sentences, review history and study statistics. All of this lives in a local database on your device.
- Your pronunciation recordings. Practice recordings are scored on-device and are not uploaded.
Deleting the app deletes all of this permanently.
What we collect
1. Account information — only if you sign in
LinguaFlow can be used without an account in guest mode. If you choose to use Sign in with Apple, we receive:
- Your email address (or Apple's private relay address, if you chose to hide your email)
- A user identifier used to associate your account with your subscription and daily usage allowance
We use this only to identify your account, apply your subscription, and enforce the free tier's daily AI limit. We never use it for advertising and never sell it.
Authentication and account storage are handled by Supabase (Supabase Inc.), acting as our data processor.
2. Text you explicitly send to AI features
When you tap Explain on a subtitle line, the app sends to our server:
- The single sentence being explained
- Your approximate learner level and chosen language
That text is forwarded to OpenAI to generate the explanation, and the result is cached on your device so repeat views cost nothing.
This only happens when you actively tap an AI feature. No audio is sent — only text. Video, audio files and full transcripts are never sent.
OpenAI processes this data as our provider under their API terms and, per those terms, does not use it to train their models.
3. Subscription status
If you subscribe to LinguaFlow Pro, Apple processes the payment. We never see your payment details. We receive and store only the transaction identifier and whether your subscription is active, so the app can unlock Pro features across your devices.
4. Feedback you send us
If you use Send Feedback, your email app opens with a prefilled message containing your app version, iOS version and device model. You can edit or remove any of it before sending. We receive whatever you choose to send.
5. Reporting a For You clip
If you report a problem with a For You clip, we receive the reason you choose and, if you're signed in, your account. We use it only to fix or remove the clip. For You plays each clip in YouTube's own player, so YouTube's privacy policy covers what that player does.
What we do NOT do
- We do not track you across other apps or websites.
- We include no advertising SDKs, and no analytics or crash-reporting SDKs.
- We do not sell or rent your personal data to anyone, ever.
- We do not create advertising profiles.
- We do not access your photo library beyond the specific video you pick.
Permissions the app asks for
| Permission | Why | Optional? |
|---|---|---|
| Microphone | Recording your voice for shadowing practice and pronunciation scoring | Yes — only needed for Practice |
| Speech Recognition | Transcribing video audio and scoring pronunciation | Yes — needed to process videos |
| Photo library | Only the specific video you choose to import | Yes — you can import from Files instead |
A note on speech recognition
LinguaFlow uses on-device speech recognition by default. If the on-device Chinese model is unavailable, the app will ask for your explicit permission before sending audio to Apple's servers for transcription. This never happens silently, and you can turn it off at any time under Me → Server Speech Recognition. Any such processing is covered by Apple's Privacy Policy.
Children's privacy
LinguaFlow 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 personal data, contact us and we will delete it.
Your rights and choices
- Use the app anonymously. Guest mode requires no account.
- Delete your account and all associated data at any time, directly in the app: Me → Delete Account. This permanently erases your account, email, subscription record and cached AI responses from our servers. It cannot be undone.
- Delete local data by deleting the app.
- Request a copy of your data by emailing suryapradipta@icloud.com.
If you are in the EEA or UK, you have rights under GDPR to access, correct, export, restrict or erase your data, and to object to processing. If you are in California, you have rights under CCPA/CPRA — note that we do not sell personal information. Email us to exercise any of these; we respond within 30 days.
Our legal basis for processing under GDPR is performance of a contract (providing the app's features you request) and consent (optional features such as server-based speech recognition).
Data retention
- Account data is kept until you delete your account.
- Cached AI responses are kept until you delete your account or the app.
- We do not retain video, audio or transcript content at all, because we never receive it.
International transfers
Our processors (Supabase, OpenAI) may process data on servers outside your country, including in the United States, under appropriate safeguards such as Standard Contractual Clauses.
Third-party processors
| Processor | Purpose | Policy |
|---|---|---|
| Supabase Inc. | Authentication, account storage, backend functions | https://supabase.com/privacy |
| OpenAI, L.L.C. | Generating AI explanations | https://openai.com/policies/privacy-policy |
| Apple Inc. | App distribution, subscriptions, optional server speech recognition | https://www.apple.com/legal/privacy/ |
| Google LLC (YouTube) | Playing For You clips in YouTube's own player | https://policies.google.com/privacy |
Security
Data in transit is encrypted with TLS. Backend access is protected by authenticated requests and row-level security, so one account cannot read another's data. AI provider keys are held server-side and never shipped in the app.
Changes to this policy
If we make material changes we will update the date at the top of this page and note the change in the app's release notes.
Contact
Questions about this policy or your data: