Languagetool Libreoffice

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N-grams usage is not promoted in this project since the files are too big to be packaged with the main program, and they make the program too slow to be used for real-time checking (see 1956c54). #### LibreOffice / Apache OpenOffice Integration. default rule underline style is 'bold wave'. Only applies to LibreOffice version 6.3.0 or superior. LanguageTool is a style and grammar proofreading software for English, French, German, and a lot of other languages. You can think of LanguageTool as a software 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. LanguageTool integrates with word processing software including Microsoft Word for Windows and Mac, Google Docs, LibreOffice, and FidusWriter.

One of the software products which Linux has traditionally been lacking in, is grammar-checking software, that runs off-line. And one such package that I’ve been keen on getting to work, under Debian / Stretch as well as under the older Debian / Jessie, is LanguageTool. Why this LibreOffice extension? Because I would mainly want German and English support, while the product also offers some French support, the last of which can always come in handy in a Canadian province, which is officially French-speaking. The need can always arise, to write some letter in French, and a letter in which the grammar will need to be correct.

There do exist other proprietary solutions, but none which add full support for German.

When I write that I’ve been ‘keen on getting (this) to work’ , I’m referring to the fact that this extension can be a bit temperamental. As I was activating version 4.3 on my Debian / Jessie laptop ‘Klystron’ , I noticed that I had versions 2.3 and 3.8 already-downloaded there, that were left on my hard drive from past, forgotten failures. So, what I learned while installing v4.3 on ‘Plato’ , my main, Debian / Stretch computer, would be put to the test. If the attempt to install v4.3 on ‘Klystron’ also, worked on my first try, then these would be valid observations made, when previously working to get the same version working on ‘Plato’ . And my result was, that I could get v4.3 to work on ‘Klystron’ as well, on the first try!

( Screen-Shot from the computer ‘Plato’ . )

During my recently-failed attempt to get this extension working on ‘Plato’ , I had gotten to a series of error-messages while clicking on ‘Tools -> LanguageTool -> Options…’ , that amounted to Java Null-Pointer Exceptions. Usually, such exceptions would indicate some serious programming error. But what I found was that I could get the extension to work, if I followed 4 basic guidelines:

(Updated 12/25/2018, 14h20 … )

(As of 12/22/2018, 22h00 : )

  1. Make sure I had the Linux package ‘libreoffice-java-common’ installed (I had not, on both machines),
  2. Make sure that my software-versions, both of LanguageTool and of LibreOffice, were up-to-date, meaning this is only tested to work under LibreOffice 5.x ,
  3. Within LibreOffice, make sure that Oracle Java 8.x is selected as the JRE to use, under ‘Tools -> Options -> LibreOffice -> Advanced’ ,
  4. Make Sure that I had The native grammar-checker ‘LightProof’ Disabled, which can be done by drilling down into ‘Tools -> Options -> Language Settings -> Writing Aids’ .

After having done all this, then having installed LanguageTool, and having restarted LibreOffice with everything set up correctly, even the mysterious Null-Pointer Exception gave way, to a smoothly-running extension, that offered some basic style corrections, when running tests which I had crafted. It appears that even a Null-Pointer Exception, can sometimes be due to something other than an actual programming error.

At the same time, it’s possible to pay for a subscription to ‘LanguageToolPlus‘ , even though doing so does not enable any features in the LibreOffice Extension. Doing so just makes the on-line version of the product more powerful, that can be accessed through the Web-interface, and is also a way of paying forward, the work and effort that some software-developers put, into writing software that Linux users may use for free. At the same time, paying for this product enables the browser-extensions to work, that are based on the providers’ servers, by giving users a log-in, which they can set their browser extensions to use… I for one, am now enjoying the fact that the Firefox LanguageTool extension, is advising my grammar, as I’m editing this WordPress posting, without being a WordPress plug-in.

(Update 12/25/2018, 14h20 : )

One important detail which I forgot to mention above is, the fact that the installation of the LanguageTool extension will hide the existence of the internal ‘LightProof’ grammar-checker from view, perhaps in a failed attempt to automate disabling it. What I found was that I actually needed to disable LightProof manually, with LanguageTool not installed (according to Step 4 above), before installing LanguageTool, in order for the installation to succeed.

Languagetool para libreoffice

Languagetool Libreoffice Ubuntu

On my Debian / Jessie laptop named ‘Klystron’ , I’ve found that sometimes, the Null-Pointer Exception can come back, when I click ‘Tools -> LanguageTool -> Options’ . For the moment, this error message was avoidable, when coming to step (3) above, I did not just acknowledge LibreOffice displaying the available Java Run-Times, and choosing the correct one by default, but rather, by seeing that the correct one was chosen by default, and then clicking ‘Ok’ , as if to do so added something to my personal preferences. Apparently, LibreOffice having the ability to detect the available JREs in the background, and ‘knowing’ which one is correct, is not the same thing, as the user having selected the correct JRE.

Languagetool Libreoffice

At the same time, I’m skeptical about claims on the LanguageTool Web-site, that the JRE version must be “at least 8.x”. Java Run-Times are often finicky, and while the Windows world has moved on to Java 10, I would not just assume that this extension works with Java 10. I guess it’s just good news for me then, that the two Debian versions I’m presently running, receive Java 8 from their package repositories.


If installation of LanguageTool in LibreOffice/OpenOffice didn't throw an error but you are not sure if it actually works, please load this document and follow the instructions in it.

Common issues

  • LibreOffice comes with its own integrated grammar checker (LightProof) which disables LanguageTool for English and Russian. Use Options -> Language Settings -> Writing aids -> Edit... to disable LightProof and enable LanguageTool for the language you are working with to make LanguageTool work.
  • Make sure Java 8 or later is selected in LibreOffice (Tools -> Options -> Advanced) or (Tools -> Options -> Java). For Mac users: LibreOffice (Preferences -> LibreOffice -> Advanced).
  • Note that if you have a 32-bit version of LibreOffice/OpenOffice, you will also need a 32-bit version of Java - LanguageTool will not work otherwise. Apache OpenOffice doesn't provide official 64-bit versions for Windows and Mac yet, so you will need a 32-bit Java on Windows and Mac.
  • If you get 'Could not create Java implementation loader': If you have this problem on 64-bit Windows, it may be caused by a 64-bit version of Java. Apache OpenOffice on Windows is only built as a 32-bit application and will not work with a 64-bit Java. You need to use a 32-bit build of Java for Windows. (OOo bug #118346). If that doesn't help, please try these suggestions.

Other issues

Languagetool libreoffice 7

Chinese Grammar Checker

  • If you get 'This media-type is not supported: application/' during installation, please consider resetting your OpenOffice user profile.
  • If you get an error that says 'Invalid memory access', make sure LanguageTool is installed in a path that has no special characters (use a-z, A-Z and 0-9 only).
  • If you get 'Failed to load rules for language ... Caused by java.lang.ClassNotFoundException: Loading rules failed: Duplicate class definition': For some reason LanguageTool is installed twice as an extension in LibreOffice/ You can try deleting the directories listed in the error message after making a backup. (The directories to be deleted have random names like 'EE31.tmp_' or similar - exit LibreOffice/ before deleting anything).

Languagetool Libreoffice

If LanguageTool still doesn't work properly for you, please post to the forum describing the problem and letting us know which version of LanguageTool, LibreOffice/ and which operating system you are using.