Terms of use

What Moien offers, what it does not promise, what you may do with the course, what donating a recording allows, and the rules of the chat rooms. Last updated 18 October 2026 (the optional public link to a certificate: section 2). Before that, 16 October 2026 (the certificate of completion is now kept for you, so that it is signed once: section 2). Before that, 16 October 2026 (the certificate of completion, issued by Valnivo Sign for Moien, for your Google account: section 2). Before that, 16 October 2026 (a donated recording may now be one line of a conversation, not only a word, and donors are asked again: section 6; the message check may run on our server by your choice, section 11). Before that, 12 October 2026 (one small advertisement at the end of a few pages of the website, section 3). Before that, 9 October 2026 (the synthetic voice, before section 8; how long chat messages are kept, section 11). Before that, 2 October 2026 (the chat rooms, section 11). Before that, 30 September 2026 (no advertising; the course text under CC BY-SA 4.0; the levels). The privacy notice says how your data is handled; these terms do not change it.

1. Who offers Moien

Moien is developed and offered by Valnivo Labs, based in Luxembourg. Valnivo Labs is a trade name, not a registered company. You can reach it at contact@luxembourgish.app, and about your data at privacy@luxembourgish.app.

2. What Moien is

A free course in Luxembourgish, most of it at A1 to B1, with lessons up to C2, on the website luxembourgish.app and in the Moien Android app. You can use all of it without an account. Signing in with Google is optional: it carries your progress between your devices and lets you join the chat rooms (section 11).

When you have finished a level and are signed in with Google, you can download a certificate of completion as a PDF issued by Valnivo Sign for Moien. Moien and Valnivo Sign are products of Valnivo Labs. It is made for your Google account and carries that account’s name. It records that the synced progress record of your Google account showed every lesson of the level as passed when it was issued; Moien does not check how that record was made. It is not an official qualification, it has nothing to do with the INLL, the Ministry of Education or the Sproochentest, and it is not a qualified electronic signature. Anybody can check that the file is the one Valnivo Sign issued for Moien, on Moien’s /check page or on the check page of Valnivo Sign, from the file alone. The signed certificate is issued once and kept for you, in a private storage bucket in the European Union, so that you can download it again at any time and it is never signed twice; the privacy notice (section 5c) says what is kept and who can reach it. Deleting your account deletes the certificates kept for it.

You may also choose to make a certificate viewable by anyone who has a link, so that a LinkedIn post carrying it shows a preview card. That is your own choice and your own responsibility: anyone with the link can see the certificate, including your Google account’s name, and can share it. Create it only if you are content with that, and share the link only where you mean to. You can turn the link off at any time, which deletes the public page and picture; copies that others, or LinkedIn, fetched while it was on are outside Moien’s control. Deleting your account deletes the link too. The privacy notice (section 5c) says what the page shows and what is kept.

3. Moien is free

Moien costs nothing and sells nothing. To help pay for running it, the website shows one small advertisement, labelled “Sponsored”, at the end of a few pages (the home page, the list of lessons, the vocabulary, a word’s page and the verbs), never in a lesson, an exercise, the review, the placement test or the chat; the Android app shows none. The advertisement is Google’s, not ours, and we do not endorse what it offers. Because it is free, it is offered as it is: features may change, be added or be removed, and the service may pause or stop. You acquire no right to it continuing, and there is nothing to refund.

4. The course

The lessons are written with care, follow the official Luxembourgish orthography and draw on the Lëtzebuerger Online Dictionnaire, but they may contain mistakes. Moien is a way to learn, not a qualification: it is not affiliated with the INLL or the ZLS, its Sproochentest practice is not the examination, and it cannot promise that you will pass one. If you find a mistake, the About page says how to report it.

5. Using it fairly

• Use Moien for learning, your own or someone else's.
• Do not try to break, overload or get around the service or its security.
• Your account is yours: keep your Google sign-in to yourself. You can delete your account and everything stored with it on the Settings and data page at any time.

6. Recordings you donate

This applies only if you opt in to donating recordings, and only to the recordings you choose to send.

• They must be yours. By sending a recording you confirm that it is your own voice saying the word, or the line of a conversation, you were asked to say, and that you are 16 or older.
• What you allow. You give Valnivo Labs a free, non-exclusive, worldwide permission to store the recording, to listen to it and have it checked, and to use it to test and train speech-recognition models for Luxembourgish, and to publish the trained models openly so that the app and anyone else can use them. A trained model contains no recording.
• What you do not allow. Recordings are never published, sold or shared as recordings, and they are not used for anything else.
• Withdrawing. "Stop and delete my recordings" on the Settings and data page deletes your recordings and ends this permission for them. A model trained before you withdrew cannot unlearn them and stays published, but it holds no recording of you.

How long recordings are kept and who can hear them is in section 5a of the privacy notice.

7. What belongs to whom

The course text (the lessons, with their words, notes, examples, grammar notes and exercises) is published under the Creative Commons Attribution-ShareAlike 4.0 licence (CC BY-SA 4.0): you may share and adapt it, for any purpose, as long as you credit Moien and share what you make from it under the same licence. The app itself, the name Moien and its mark stay Valnivo Labs', and that licence gives no right to them. The pronunciation recordings are open data from the Lëtzebuerger Online Dictionnaire, and the speech models come from the University of Luxembourg's LuxASR, each under its own licence.

The audio in Moien is separate from the course text. A recording is a speaker's recording from the dictionary, published there as open data (CC0). A phrase or sentence that no speaker recorded is read by a synthetic voice made by the ZLS, and its listen button says so.

8. Responsibility

Moien is provided free and as it is. Valnivo Labs is responsible for damage it causes intentionally or through gross negligence. Beyond that, and as far as the law allows, it is not liable for what follows from using the course, from its mistakes, or from the service being unavailable. Nothing in these terms limits a responsibility the law does not allow to be limited, or takes away a right you have as a consumer.

9. Changes

These terms may change. The date at the top changes with them. If a change affects what donating a recording allows, you will be asked again before any new recording is sent under it.

10. Law

These terms are governed by Luxembourg law. If you are a consumer, you keep the protection of the law of the country where you live, and you may bring a claim before its courts.

11. Chat rooms

This applies only if you join the chat rooms, which are for people aged 16 or older, signed in with Google.

• What they are for. Practising Luxembourgish with other learners, and talking about learning it. Write in Luxembourgish as far as you can; other languages are welcome when they help.
• What is not allowed. Insulting, threatening or harassing anyone; hatred against anyone for who they are; sexual content; advertising, spam or links to sell something; pretending to be someone else; sharing anyone's personal details, your own included; and anything illegal. Do not use the rooms to meet people under 16, and do not join if you are under 16.
• Words the chat refuses. Messages, room names and chat names containing a word on the chat's list of slurs and abusive words are refused. If a word was refused wrongly, ask for a review from the message itself; Valnivo Labs reads it and corrects the list when it was wrong.
• The message check. Using the chat requires a small AI model that runs on your device (installed) or, if you choose, on our server (privacy notice, section 2), and, before you send a message, may ask you to look at it again, or refuse it when it is sure the message is insulting or abusive; a refused message can be sent for review. It is AI and can be wrong; it never sends what you write anywhere. Sending a message it warned about is your decision and your responsibility.
• Reported and refused messages train the check. When a message is reported, or a refused message is sent for review, a copy of its text with names, addresses and links removed may be used to train and test the message check, as section 5b of the privacy notice describes; the model may be published, the texts never are.
• Your messages are yours. You are responsible for what you write. You give Valnivo Labs the permission it needs to store your messages and show them to the other members, for as long as they are kept (they expire after 30 days and the next weekly clean-up deletes them), and, for a message that is reported or sent for review, to use its scrubbed copy as the item above says; no other.
• Rooms are looked after by their creators. Whoever opens a room may delete messages in it and ban people from it. A creator who abuses that is breaking these rules too. A room ends, with everything in it, after 5 hours without a message or as soon as it is empty.
• Reports and what Valnivo Labs may do. Anyone can report a message; the report goes to the room's creator and Valnivo Labs can read it. Valnivo Labs may delete messages or rooms, and end someone's membership of the chat, when they break these rules or the law, and will say why to the address of the Google account concerned when it ends a membership. Something illegal can also be reported to support@luxembourgish.app. If you think a decision about you was wrong, write to the same address.
• Leaving. "Leave the chat and delete what I wrote" deletes your rooms, your messages and your chat membership at once. What the chat stores and for how long is in section 5b of the privacy notice.

Last updated 18 October 2026 (the optional public link to a certificate: section 2). Before that, 16 October 2026 (the certificate of completion is now kept for you, so that it is signed once: section 2). Before that, 16 October 2026 (the certificate of completion, issued by Valnivo Sign for Moien, for your Google account: section 2). Before that, 12 October 2026 (one small advertisement at the end of a few pages of the website, section 3). Before that, 9 October 2026 (the synthetic voice, before section 8; how long chat messages are kept, section 11). Before that, 2 October 2026 (the chat rooms, section 11, with the words the chat refuses, rooms that end, the message check and training it on reported messages). Before that, 30 September 2026 (no advertising; the course text under CC BY-SA 4.0; the levels).