Practice is personal.

1. Scope and current status

This Privacy Policy applies to lingounion.com and the LingoUnion iPhone app available on the US App Store. LingoUnion is the product name used by Hongyu Zhang, an individual developer and operator. In this policy, “LingoUnion,” “we,” “us,” and “our” refer to Hongyu Zhang.

LingoUnion version 1.0 is publicly available. Version 2.0 adds AI-generated translations and speech for 20 target languages. This policy describes the version 2.0 data practices that apply when those features are made available.

2. This website

The first version of this website does not include account registration, payment, advertising, marketing forms, or behavioral profiling. We do not place our own advertising cookies or add third-party marketing trackers.

The website is delivered through Cloudflare. Like most internet infrastructure providers, Cloudflare may process standard technical request information such as IP address, request time, browser information, and requested URL to deliver and protect the site. Cloudflare handles that information under its own terms and privacy documentation.

If privacy-friendly site analytics are added later, this policy will be updated before those analytics are enabled.

3. Learning data stored by the app

The app stores the information needed to organize learning on the current iPhone. This may include:

• the short native-language sentences you choose to practice;
• the corresponding US English target sentences;
• completion counts, necessary match scores, and review dates;
• the selected US English system voice identifier;
• content-free capability status and fixed diagnostic error codes.

These learning records remain in the app’s protected storage on the iPhone where they were created. For an AI generation you request, the current source sentence and generated target sentence are transmitted as described below. LingoUnion does not send your practice transcript, microphone recording, handwriting, match results tied to sentences, or learning history to its gateway or OpenAI.

Speech and handwriting

Audio used for a current speech-recognition attempt is held only as needed for that attempt and is not retained as a learning record by LingoUnion. A current transcript is used to show and calculate the match result, then cleared when that result state ends. LingoUnion does not obtain or store the original pen strokes entered through the iPhone system handwriting keyboard.

4. AI generation and Apple system services

Information sent for AI generation

When you request a new sentence, LingoUnion sends the source sentence, source and target language codes, selected voice, and content-generation request details through our Cloudflare gateway to OpenAI. OpenAI returns a translation and generated speech audio. The gateway does not persist the sentence, translation, prompt, OpenAI response, or audio.

OpenAI states that API inputs and outputs are not used to train its models by default unless the API organization explicitly opts in. LingoUnion’s OpenAI organization sharing controls are disabled. Under OpenAI’s standard retention, eligible input and output content may still appear in abuse-monitoring logs for up to 30 days, and may be kept longer when required for legal or safety reasons. LingoUnion has not been approved for or enabled Zero Data Retention.

The in-app AI notice appears before the first AI request. You may decline it or withdraw consent later; LingoUnion will not send another AI request while consent is withdrawn.

Apple system services

Speaking practice uses Apple speech recognition, and handwriting uses the iPhone system keyboard. Depending on the iPhone, iOS version, region, settings, installed language resources, and network state, Apple may process information on the device or through Apple-operated services. LingoUnion does not send the microphone recording or recognized practice transcript to OpenAI.

Apple’s handling of speech recognition, handwriting, App Store purchases, and system diagnostics is governed by Apple’s applicable privacy terms and system settings.

5. Subscriptions and purchases

Subscriptions are purchased and managed through Apple’s App Store using StoreKit. The app evaluates Apple-verified status on the iPhone, and version 2.0 also sends a current signed subscription proof to the LingoUnion gateway so the gateway can verify current access with Apple before providing paid AI generation.

The gateway handles the signed proof only for the current verification request and does not persist the full proof, transaction identifier, original transaction identifier, Apple Account credentials, or payment-card details. It stores keyed, non-reversible subscription and entitlement digests needed to authorize the service and enforce the shared one-sentence-per-day allowance.

The app does not store a transaction identifier, original transaction identifier, full signed transaction, or full JWS in its offline subscription proof or ordinary logs. That limited proof is kept in a protected, backup-excluded file within the app and is removed when the app is deleted.

Subscription information is kept separate from learning content. LingoUnion does not use a sentence, recording, transcript, handwriting entry, or learning-history identifier to recognize a subscriber.

Apple processes App Store accounts, payment details, purchase records, and refund requests under Apple’s terms. LingoUnion does not receive an Apple Account password, full payment-card information, or two-factor authentication code.

6. Diagnostics and support

The app contains no third-party analytics SDK, third-party crash-reporting SDK, advertising tracker, or developer-operated diagnostic upload. Version 2.0 uses the LingoUnion gateway only for App Attest authentication, current-subscription verification, daily allowance enforcement, and AI content generation; this is the app’s only custom business-data network client. App-owned ordinary logs are limited to fixed operational codes and nonnegative aggregate counts; they do not accept free-form learning or transaction text.

Apple may collect or provide system diagnostics according to the user’s iPhone settings and Apple’s terms. LingoUnion does not add learning content or full signed transaction data to an app-owned crash report or support package.

Support may ask for basic device, app-version, error-code, and subscription-status information. Please do not send learning sentences, target English sentences, transcripts, recordings, handwriting, learning history, passwords, verification codes, payment details, or signed transaction data.

7. Retention, backup, and deletion

Learning records remain on the current iPhone until you delete a sentence, delete all learning data in the app, or delete the app. LingoUnion does not provide learning-data cloud backup, sync, export, migration, or cross-device recovery.

Deleting learning data in the app does not delete Apple’s App Store purchase history or subscription records. Those records are controlled by Apple.

The gateway retains keyed, non-reversible device, subscription, entitlement, request, and daily allowance records only as needed to authenticate the app, enforce access and daily limits, prevent duplicate generation, protect the service, and resolve operational integrity issues. These records do not contain the sentence, translation, prompt, audio, raw App Attest key, full Apple proof, or Apple Account credentials. Deleting local learning data does not reset the daily allowance or delete these integrity records.

OpenAI’s standard API retention is described in section 4. OpenAI abuse-monitoring logs may retain eligible inputs and outputs for up to 30 days, with longer retention possible for legal or safety reasons.

8. Security

LingoUnion is designed to use protected iPhone app storage, exclude learning records from app-managed cloud backup, avoid putting learning content in ordinary logs or filenames, clear temporary recognition data, cover learning content when the app enters the background, require App Attest for the gateway, and use encrypted transport.

No storage or transmission method is absolutely secure. We maintain safeguards appropriate to the information and update this policy if the product’s security or data flow changes materially.

9. Your choices

• You choose the sentence you enter and may delete it later.
• You may decline or withdraw AI data-processing consent; AI generation will then be unavailable.
• You may delete all LingoUnion learning records stored on the current iPhone.
• You control relevant Apple permissions and system settings.
• You can manage or cancel a subscription through your Apple Account.
• You may contact us with a privacy question without sending learning content.

Because LingoUnion does not maintain an account or developer-operated copy of your learning records, we generally cannot retrieve, export, or restore those records for you. You may contact us about the limited gateway integrity records using the address below.

10. Adults only

LingoUnion is intended for people age 18 or older and is not directed to children. It is not offered in the App Store Kids Category.

11. Changes to this policy

We may update this policy to reflect product, legal, or operational changes. The “Last updated” date at the top identifies the current version. Material changes will be presented through an appropriate website or in-app notice before or when they take effect.

12. Contact

Operator: Hongyu Zhang, individual

For privacy questions, email support@lingounion.com with the subject “Privacy question.” Support is provided in English.

Do not include learning content, recordings, transcripts, handwriting, passwords, payment information, or signed transaction data in your message.