Check your language and grammar everywhere like a pro with LanguageTool

LanguageTool is written in Java. The last couple of years I just downloaded the server .jar and ran it locally. This, however, came with a delay for starting the server. Also, it can be a nightmare to get the correct java runtime set up correctly.

This is why I recently was happy to find that there are up-to-date docker images available. With that, a setup is as easy as setting up a docker-compose file and making sure it starts with my computer. The following docker-compose.yml sets up a local LanguageTool server that can be reached at localhost:8081, the default for most applications and add-ons (see below):

version: "3"

services:
  languagetool:
    image: erikvl87/languagetool
    container_name: languagetool
    restart: unless-stopped
    ports:
        - 8081:8010  # Using default port from the image
    environment:
        - langtool_languageModel=/ngrams  # OPTIONAL: Using ngrams data
        - Java_Xms=512m  # OPTIONAL: Setting a minimal Java heap size of 512 mib
        - Java_Xmx=1g  # OPTIONAL: Setting a maximum Java heap size of 1 Gib
    volumes:
        - ./ngrams:/ngrams

If you want even better language checking, you can download more complex (but also more voluminous in terms of required disk-space) "n-grams" data. At the time of writing, these language models are available in English, German, French, Spanish and Dutch. Just download the ones you need and extract the zip-files into a folder ngrams next to your docker-compose.yml. The only thing that is now necessary is to run sudo docker-compose up -d from within the directory and everything should work just fine. If you want to check the logs of the docker, you can use sudo docker-compose logs -f (again, from within the directory).

To spell-check your text inside your browser, you can install the add-on from the respective store, e.g. for Firefox. By default, the add-on uses the LanguageTool servers. You can, however, change the server address to use your freshly installed local server. Thus, no data leaves your machine. For that, just click on the LanguageTool icon in your browser's toolbar, click the Settings icon and go to "Experimental Settings (only for advanced users)". Here you can select to use a local server and "Save" to confirm:

While the official LanguageTool LibreOffice extension provides a small language model itself, you can make use of your new local server with the ngrams language models. Just go to Extension → LanguageTool → Options…, under General select Use remote server to check text and enter the http://localhost:8081 as the server address.

TeXstudio is, in my opinion, one of the best LaTeX editors out there. This is in large parts due to the easy integration with LanguageTool. In fact, it was through TeXstudio that I discovered LanguageTool in the first place.

Once you have a local LT server running, you just have to add it to LanguageTool like this: Click Options → Configure TeXstudio → Language Checking and add the following configuration

Even from within Emacs, the beloved text editor from the 70s, it is possible to check spelling. Thanks to the awesome langtool package by Masahiro Hayashi, it is as easy as to add some use-package lines to your init.el:

  (use-package langtool
:ensure t
:config
(setq langtool-http-server-host "localhost"
   langtool-http-server-port 8081) )

With my setup using EVIL-mode and EVIL-leader, it is as easy as to SPC l l to start LanguageTool and check my text and SPC l c to enter spell checking. Here you can see how suggestions are presented: