Privacy Policy

Introduction

Echo回声练习 ("we", "our", or "the App") is an English listening and speaking practice app. This Privacy Policy explains what data the App handles, how it is processed, and the limited circumstances in which practice text is sent to third-party services with your explicit consent.

Data Processed On-Device Only (Never Uploaded)

The following data is processed entirely on your device and is never transmitted to any server:

• Voice recordings: Shadowing/pronunciation recordings are analyzed by an on-device speech recognition model (Whisper, running locally). Recordings never leave your device.
• Photos and camera images: Text recognition (OCR) is performed on-device using Google ML Kit. Images never leave your device.
• Learning data: Practice history, vocabulary lists, and statistics are stored locally on your device only.
• App preferences: Settings and customization choices are stored locally.

Data Sent to Third-Party Services (Only With Your Consent)

Two optional features send your practice text to third-party AI services. Before either feature is used for the first time, the App shows an in-app notice that explains what data is sent, who receives it, and why, and asks for your permission. You may decline and use the App fully offline, and you can change your choice at any time in Settings → Privacy.

1. Online Speech Synthesis (Edge TTS)

• What is sent: The English sentences you practice and text you type into the App.
• Who receives it: Microsoft Corporation (Edge TTS service).
• Why: To generate high-quality natural pronunciation audio.
• If you decline: The App uses your device's built-in text-to-speech instead, and no text is sent anywhere.
• Microsoft's privacy policy: https://privacy.microsoft.com/privacystatement

2. Online Translation (MyMemory)

• What is sent: The English sentences and words you choose to translate.
• Who receives it: MyMemory / Translated (Translated S.r.l., Italy).
• Why: To provide Chinese translations of your practice sentences.
• If you decline: The App uses its built-in offline dictionary instead, and no text is sent anywhere.
• MyMemory's privacy policy: https://translated.com/privacy

Model Downloads

On first use of on-device speech recognition, the App downloads the Whisper model file from Hugging Face (huggingface.co). This is a one-way download of a model file; no user data is sent in this request.

How We Collect Data

• On-device data (recordings, images, learning progress) is created by your direct use of the App and stored only in the App's local storage (SQLite database and app documents directory) protected by the iOS sandbox.
• Practice text is sent to third parties only through the two consented features described above, over encrypted HTTPS connections.

Data We Do NOT Collect

• No user accounts, names, email addresses, or contact information
• No advertising identifiers or analytics trackers
• No location data
• No voice recordings or photos on any server

Data Retention and Deletion

• All local data remains on your device until you delete it in the App or uninstall the App.
• Temporary audio caches are cleared automatically.
• Text sent to Microsoft or MyMemory is processed transiently to return audio/translations; we do not operate any server that stores it.

Children's Privacy

The App is suitable for all ages. We do not knowingly collect personal information from anyone. All personal content remains on the device under the device owner's control.

Your Rights and Choices

• Withdraw consent anytime: Settings → Privacy → toggle off "Online Speech" / "Online Translation". The App immediately stops sending text and falls back to on-device voice and offline dictionary.
• Delete your data: Clear data in Settings → Data, or uninstall the App.
• Use fully offline: Declining consent does not affect core functionality (listening practice, shadowing, OCR, vocabulary).

Changes to This Policy

If we update this policy, we will post the new version at the same URL and update the "Last Updated" date. If changes affect data sharing, we will ask for your consent again in the App.