LanguageTool is an Open Source proofreading software for English, French, German, Polish, Russian, and more than 20 other languages. It finds many errors that a simple spell checker cannot detect.

LanguageTool is freely available under the LGPL 2.1 or later.

For more information, please see our homepage at https://languagetool.org, this README, and CHANGES.

The development overview describes how you can contribute error detection rules.

See 'easy fix' issues for issues to get started.

For more technical details, see our wiki.

Before start: you will need to clone from GitHub and install Java 8 and Apache Maven.

Warning: a complete clone requires downloading more than 360 MB and needs more than 500 MB on disk. This can be reduced if you only need the last few revisions of the master branch by creating a shallow clone:

git clone --depth 5 https://github.com/languagetool-org/languagetool.git

A shallow clone downloads less than 60 MB and needs less than 200 MB on disk.

In the root project folder, run:

mvn clean test

(sometimes you can skip Maven step for repeated builds)

./build.sh languagetool-standalone package -DskipTests

Test the result in languagetool-standalone/target/.

./build.sh languagetool-wikipedia package -DskipTests

Test the result in languagetool-wikipedia/target.

./build.sh languagetool-office-extension package -DskipTests

Test the result in languagetool-office-extension/target, rename the *.zip to *.oxt to install it in LibreOffice/OpenOffice.

Now you can use the bleeding edge development copy of LanguageTool *.jar files, be aware that it might contain regressions.