Effective date: 2026-10-19
Version: 1.2
Applies to: Tonglo (Android application, package
cz.vanama.tonglo)
Tonglo is an English-speaking practice app. It is developed and published by an individual developer (the "Developer") based in the European Union. This policy explains what data the app processes, where that data goes, and what control you have over it.
Tonglo has no user accounts, no login, and no server of its own. Everything the app remembers about you is stored on your device. The only data that leaves your device goes to the third-party services listed in section 3.
| What | Where it goes | Why |
|---|---|---|
| Microphone audio | Your device's speech-recognition service (usually Google) | To turn your speech into text |
| Conversation text and practice answers | Google (Gemini via Firebase AI Logic) | To generate the partner's replies, evaluate your English, extract vocabulary and personal facts |
| Personal facts derived from free conversations | Stored on your device | To personalise future conversations |
| Learning data (XP, streak, badges, statistics, flashcards, profile) | Stored on your device | To run the app's learning features |
| Usage analytics | Google (Firebase Analytics) — only if you opt in | To understand which features are used |
| Crash reports | Google (Firebase Crashlytics) — release builds only | To diagnose crashes |
| Text the app reads aloud — only if you choose a voice that needs the internet | Your device's text-to-speech service (usually Google) | To speak the AI partner's replies |
| A reported AI reply — only when you send the e-mail yourself | The Developer, by e-mail from your own mail app | To review and fix inappropriate or wrong AI content |
Tonglo does not sell your data, does not show ads, and does not use advertising or cross-app tracking identifiers.
The following is stored locally on your device only. It is never uploaded to a Tonglo server, because no such server exists.
This data is held in an on-device database (Room) and in on-device preferences (DataStore). Uninstalling the app deletes all of it.
When you tap the microphone button, Tonglo asks Android's system speech-recognition service to transcribe what you say. On most Android devices this service is provided by Google and performs recognition on Google's servers; the app falls back to on-device recognition only if the online service is unreachable.
Tonglo itself does not record, store, or transmit audio. It receives only the resulting text. The handling of the audio is governed by the privacy policy of the speech-recognition provider on your device — on Google-based devices, Google's privacy policy (https://policies.google.com/privacy).
The microphone is only active while you are holding a practice
session and have started listening. While the microphone is on,
everything it hears is transcribed, including other people talking
nearby, and that transcript is sent to the AI. The app requests the
RECORD_AUDIO permission at runtime; if you deny it,
conversations can still be finished by typing your answers, other
speaking practice is unavailable, and the rest of the app works.
To provide conversation practice, Tonglo sends text to Google's Gemini model through Firebase AI Logic. Specifically, the app sends:
Anything you say during a session is sent to Google as text. Please do not share sensitive personal information (health, financial, credential, or identity data) during practice.
Tonglo does not store these transcripts on any server, and does not send your name, device identifiers, or contact details along with them. Google's processing of this data is governed by the Google APIs Terms of Service and the Gemini API additional terms (https://ai.google.dev/gemini-api/terms). Google may process the content transiently to return a response and for abuse monitoring.
Firebase App Check is used to verify that requests come from a genuine installation of the app.
Usage analytics are disabled by default and are only collected if you explicitly enable them (during onboarding or in Settings). Analytics are never collected in development builds.
If enabled, the following events are recorded:
onboarding_completed, scenario_started,
scenario_message_sent, scenario_completed,
flashcard_started, flashcard_completed,
streak_extended, xp_awarded,
free_conv_completed, and ai_content_reported.
Their parameters are non-personal (scenario id, card id, message count,
word count, accuracy score, streak days, XP amount, report reason).
Two user properties are recorded: proficiency_level
(your self-declared level) and xp_tier
(beginner / intermediate /
advanced). Firebase Analytics also generates a pseudonymous
app-instance identifier and collects standard device information (device
model, OS version, country, language). No conversation content is ever
sent to Analytics.
You can turn analytics off at any time in Settings → Share anonymous usage data. Turning it off stops collection from that moment on.
Release builds of the app report crashes to Firebase Crashlytics. A crash report contains the stack trace, device model, OS version, app version, and a pseudonymous installation identifier. It does not contain conversation content, your name, or your personal facts. Crash reporting is not active in development builds.
Tonglo reads the partner's replies, flashcard prompts and the voice preview aloud using Android's text-to-speech service. By default it picks a voice installed on your device, so the text is turned into speech on the device.
In the persona editor (Voice) you can also choose a voice that needs an internet connection; such voices are offered only while you are online. With such a voice, the text the partner reads (its replies and the voice preview) is sent to the provider of your device's text-to-speech service (on most devices Google) to produce the audio. This is governed by that provider's privacy policy — on Google-based devices, Google's privacy policy (https://policies.google.com/privacy). To keep all speech on the device, set Voice to Device default or to a voice that does not need the internet.
Every AI reply has a Report this reply action. When you use it, Tonglo opens a pre-filled e-mail draft in your own mail app, addressed to the Developer. The draft contains the reason you chose and the text of the reported AI reply. Nothing is sent until you send the e-mail yourself, and you can edit or delete the draft first.
If you send it, the Developer receives the e-mail together with your
e-mail address and whatever your mail app adds. Tonglo itself does not
send the reported text anywhere; if you have enabled analytics, only the
reason code is recorded as the ai_content_reported event
(section 3.3).
Under the GDPR you also have the right of access, rectification, erasure, restriction, portability, and the right to lodge a complaint with your supervisory authority. Because the app holds your data only on your own device, access and erasure are exercised directly in the app. For anything else, contact the Developer (section 9).
Tonglo is not directed at children under 13. The app generates conversational content with a large language model and is rated for teens and older. If you believe a child under 13 has used the app, uninstalling it removes all stored data.
Material changes will be published at this address with an updated effective date and version number, and announced in the app's release notes.
Questions about this policy or about your data: martinva32@gmail.com
Czech version: privacy-policy.cs.md