Privacy Policy.

1. Who this covers

This Privacy Policy explains how Langu (“Langu”, “we”, “us”) handles your information when you create an account, access, or use the Langu application, website, or any related service (together, the “Service”). If anything here is unclear, or you want something done about your data, write to hello@speaklangu.com and a person will answer.

2. Information we collect

Only what the Service needs in order to be itself.

• An account identifier. Every install signs in anonymously the first time it runs, so you can use the Service without giving us anything at all. If you later create an account, we hold the email address, or the identifier from Apple or Google that you signed in with.
• The phrases you save, the songs you add, and how each one is going: when you last practised it, how it scored, and when it is next due.
• Which days you practised, but only once you have added a friend. It is what a shared streak is counted from, and nothing else reads it.
• Whether your subscription is active, which reaches us from the App Store through RevenueCat.

3. Information we do not collect

There is no questionnaire and no profile of you. The Service never asks which language you speak. It works that out from what you actually say or type, one request at a time, and does not store the answer. There is no age, gender, location or interests field anywhere in it, because nothing in it would be better if there were.

4. Voice and speech

When you speak to Langu, the recognition runs on your own device or in your own browser, using the speech engine your operating system already provides. The audio is not sent to us, and we never receive a recording of you.

What does leave your device is the text that comes back, which is to say the phrase you asked about. It is sent to our translation provider so that it can be answered. It is not attached to your account in that request, and neither we nor the provider use it to train anything.

5. Recordings you add

If you add your own audio file in order to practise a song against it, that file stays on your device. It is stored in your browser and is never uploaded to us. Deleting the song, or clearing this site's data, removes it.

If a recording ever does need to be measured on a server, so that the words can be timed against the audio, that request is processed and the audio is deleted as soon as it finishes. Nothing keeps a copy. All that is stored is the list of timings it produced.

6. Third party services

The Service stands on a few others. Each one sees only the part it needs.

• Google. Translation, pronunciation and song transcription run on the Gemini API. It receives the phrase or the song, and nothing about you.
• Microsoft Azure. The natural voice that reads a phrase aloud. It receives the phrase, and the voice to read it in.
• Supabase. Accounts, saved phrases and friends. Rows are readable only by the account that owns them.
• RevenueCat and Apple. Subscriptions. We never see your card. Apple handles the payment and tells us only whether the subscription is active.
• YouTube. Songs play in YouTube's own embedded player. Watching a video there is subject to Google's privacy policy, exactly as it would be on YouTube itself.
• LRCLIB. The community lyric database we look song timings up in. It receives a song title and artist, and nothing else.

7. Data stored on your device

Your settings, your saved phrases and any audio you brought are kept in your browser's own storage, so that the Service works the moment you open it. Clearing this site's data removes all of it. We set no advertising cookies and no tracking cookies for anybody else, because we sell nothing and advertise nothing.

8. Children

The Service is not directed at children under 13, and we do not knowingly collect anything from them. If you believe a child has given us data, write to hello@speaklangu.com and we will remove it.

9. Your rights and choices

You can see everything we hold, take a copy of it, correct it, or have it deleted. Delete account, inside the app, does the whole thing at once: the account and every row attached to it go, and the deletion cannot be reversed.

Depending on where you live you may have further rights, such as the right to object, to restrict processing, or to complain to your local data protection authority. Write to us either way. We would rather fix something than be complained about.

10. Changes to this policy

If this policy changes we will date the change at the top of this page, and if the change is a meaningful one we will say so inside the app rather than hope that you read the page again.

11. Contact us

Questions about any of this go to hello@speaklangu.com. We read everything.