LanguageTool Community beta

LanguageTool is an Open Source proofreading tool. This website lists LanguageTool's error detection rules and applies them to Wikipedia content for demonstration and testing purposes.


Browse Rules

LanguageTool uses rules to detect errors. Each rule represents a potential error in the text to check. Have a look at all rules of all languages here.

Check any Wikipedia page


Check Rules' Results

We use LanguageTool on Wikipedia data to test which rules work well and which need more work. If there's a real error you're encouraged to fix it in Wikipedia, but note that the check may not be up-to-date and the error may have been fixed already.

Random selection of LanguageTool results when run on Wikipedia:


  • The proper name in singular (River) must be used with a third-person verb: caters.: [Visit Rule]
    ... Facilities located along the Chattahoochee River cater to watersports enthusiasts, providing the opportu...
    Login to vote · Visit Wikipedia
  • Possible agreement error. The noun verso seems to be countable, so consider using: 80 versos.: [Visit Rule]
    ...olio 80 verso : Elm Folio 80 verso : Poplar Folio 80 verso : Willow Folio 80 verso : Osier Folio 80 verso : ...
    Login to vote · Visit Wikipedia
  • The proper name in singular (MHz) must be used with a third-person verb: ranges.: [Visit Rule]
    ...s, paired with 416 frequencies in the 869–894 MHz range for transmissions from base stations to the mobil...
    Login to vote · Visit Wikipedia
Other random examples · All matches · User votes

Visit the LanguageTool homepage to download LanguageTool as an extension for LibreOffice or OpenOffice.org