• clone the project in your own emacs configuration files directory, like:

  git clone https://github.com/ginqi7/languagetool ~/.emacs.d/lisp/languagetool;
      

• add the path to ‘load-path’

  (add-to-list 'load-path "~/.emacs.d/lisp/languagetool")
      

Here are a few variables that can be used for configuration:

(require 'languagetool)