An Open Source language checker for English, French, German, Polish, Dutch, Romanian, and other languages. This is a rule-based language checker that will find errors for which a rule is defined in its XML configuration files. Rules for more complicated errors can be written in Java. You can think of LanguageTool as a tool to detect errors that a simple spell checker cannot detect, e.g. mixing up there/their, no/now etc. It can also detect some grammar mistakes. It does not include spell checking.

Download

Try LanguageTool via Java WebStart: (requires Java 1.6_04 or later)
Start LanguageTool (17 MB)

News

2010-02-20: LanguageTool has been integrated into After the Deadline, a powerful English grammar checker. Thanks to LanguageTool it now also supports French and German. This means that you can now use LanguageTool for these languages via the After the Deadline Firefox plugin.

2009-11-01: Released version 1.0.0. Changes include:

• Support for Danish, Catalan, and Galician
• Rule and dictionary fixes for Dutch, French, Italian, Polish, Spanish, Swedish, and Russian
• More rules for Dutch, Polish, Russian, Spanish, Slovenian, and English
• Several bug fixes
• For a more detailed list of changes, see the Changelog.

Installation and Usage

• In OpenOffice.org: Double click LanguageTool-1.0.0.oxt to install it. If that doesn't work, call Tools -> Extension Manager -> Add... to install it. Close OpenOffice.org and re-start it. Type some text with an error (e.g. "This is an test." – make sure the text language is set to English) and you should see a blue underline.
• Also see Usage for using LanguageTool outside of OpenOffice.org.

Common problems with OpenOffice.org integration

• Did you restart OpenOffice.org - including the QuickStarter - after installation of LanguageTool? This is required, even if OpenOffice.org doesn't say so. (Issue 88692)
• LanguageTool installation fails if the name of your user account contains special characters. The only workaround so far seems to be to use a different user account. (Issue 95162)
• Make sure Java 5.0 or later from Sun Microsystems is installed on your system. Java versions which are not from Sun Microsystems may not work.
• Make sure this version of Java is selected in OpenOffice.org (under Tools -> Options -> Java).
• If LanguageTool doesn't start and you see no error message, please check if the extension is enabled in the Extension manager (under Tools -> Extension Manager).
• On Ubuntu, when you get an error message during installation, you might need to install the openoffice.org-java-common package. See this blog posting for details.
• LanguageTool didn't work together with the DeltaXML ODT Compare extension - use version 1.2.0 of DeltaXML ODT Compare, which fixes the problem.
• If these hints don't help, please email naber at danielnaber de describing the problem and letting me know which version of LanguageTool, OpenOffice.org and which operating system you are using.

Known bugs: Please see the README for a list of known problems.

License & Source Code

LanguageTool is freely available under the LGPL. The source is available at Sourceforge via CVS