How to change language settings in R

You can set this using the Sys.setenv() function. My R session defaults to English, so I'll set it to French and then back again:

> Sys.setenv(LANG = "fr")
> 2 + x
Erreur : objet 'x' introuvable
> Sys.setenv(LANG = "en")
> 2 + x
Error: object 'x' not found

A list of the abbreviations can be found here.

Sys.getenv() gives you a list of all the environment variables that are set.

This works from command line :

$ export LANG=en_US.UTF-8

None of the other answers above worked for me

For mac users, I found this on the R for Mac FAQ

If you use a non-standard setup (e.g. different language than formats), you can override the auto-detection performed by setting `force.LANG' defaults setting, such as for example

 defaults write org.R-project.R force.LANG en_US.UTF-8 

when run in Terminal it will enforce US-english setting regardless of the system setting. If you don't know what Terminal is you can use this R command instead:

 system("defaults write org.R-project.R force.LANG en_US.UTF-8") 

but do not forget to quit R and start R.app again afterwards. Please note that you must always use `.UTF-8' version of the locale, otherwise R.app will not work properly.

This helped me to change my console language from Chinese to English.

In the case of RStudio for Windows I succeeded in changing the language following the instructions found in R for Windows FAQ, in particular I wrote:

language = EN

inside the file Rconsole (in my installation it is C:\Program Files\R\R-2.15.2\etc\Rconsole); this works also for the command Rscript.

For example you can locate the Rconsole file with this two commands from a command prompt:

cd \

dir Rconsole /s

The first one make the root as the current directory, the second one looks for the Rconsole file.

In the following screenshot you have that Rconsole file is in the folder C:\Program Files\R\R-3.4.1\etc.

You may have more than one location, in that case you may edit all the Rconsole files.

After that you can open the Rconsole file with your favorite editor and look for the line language = and then append EN at the end of that line.

In the following screenshot the interesting line is the number 70 and you have to append EN at the end of it.