How the content is made and checked
Everything here was written for this site and is checked by 108 groups of checks that are part of the project. This page says what they check — and what they cannot.
Our own texts, nobody else’s
Every explanation, example sentence and exercise was written for this project. Nothing has been taken, translated or reworded from a textbook, a dictionary or a sentence collection — not even from freely licensed collections. Where everything else comes from, fonts, images and level names, is set out under Sources and rights.
What is checked
The project contains 120 checking tools of its own, grouped into 108 groups of checks. A few examples:
- Your browser marks typed answers by fixed rules. A separately written reference in Python marks the same test cases; if the two disagree, that counts as an error.
- Numbers, times and dates are produced a second time for 12 languages by a deliberately different calculation and compared with the first.
- Every interface text has to be there in every language, with the same placeholders.
- Every internal link and every anchor is checked.
- Every page is opened once in a browser: no script errors and not a single file from another server.
- Building twice must give the same result twice.
- “Report a mistake” is tested with protection rules deliberately broken: if a rule is missing, a check has to fail.
No AI service while you learn
No answer, no marking and no check is sent to an AI provider. Marking is done by our own code in your browser, checking by our own tools when the site is built. So no request costs anything, and what you type does not end up with such a service. One exception is outside our control: some browsers send a sentence to a service of their maker to read it aloud — which is why reading aloud only happens when you press the speaker. The images of Muno were made with AI; that too is stated under Sources and rights.
What the checks cannot do
A check finds what can be written down as a rule: a missing text, a wrong number, a dead link. It cannot tell whether an example sentence sounds natural or an explanation is clear. That is what the “Report a mistake” button is for.
Report a mistake
At the end of every grammar topic, word list, reading text and verb page there is “Report a mistake”. You choose the section and the kind of mistake and describe in 200 characters at most what is wrong. Only these details are stored, with the date, without an IP address and without an identifier. That is why there is no reply; if you would like one, write to the address in the legal notice. Details are in the privacy policy.