Privacy and local progress

No learner account

You can read every lesson and use every exercise without registration. This site has no advertising scripts or learner analytics. We do not create a learning profile on a server.

Search and exercises

Search runs in your browser with an index downloaded from this site. We do not send your search terms to a search service. The search page can include your query in its address. Avoid sensitive information if you copy or share that address.

Interactive exercises calculate results in your browser. Do not enter confidential project details into example fields. Downloaded worksheets remain under your control after download.

Optional progress storage

If you enable progress storage, this browser saves a list of completed lesson identifiers. All language versions use the same identifiers. Progress does not synchronize between devices.

Clear saved progress with the button below. You can also clear it through browser settings. Clearing browser storage or using a private session can remove saved progress.

Hosting and external links

The hosting infrastructure receives the network information needed to deliver pages. This includes your IP address and the requested URL. Operational access logs can record this information for security and service operation.

External links open services with their own privacy practices. Downloading this site does not require an account with those services.