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Multilingual R Help Pages

The rdlocal package supports translation of R help pages. Once installed, R will display documentation (for example ?function_name) in the configured language, provided a translation module is available. This will work with the HTML documentation displayed by R GUIs like RStudio, as well as with text documentation displayed by R in the console.

Translations are distributed as separate translation modules that hold the translated text for a given package’s help pages. rdlocal provides tools to generate a translation module skeleton from a package’s existing .Rd files, extracting the translatable strings into YAML files that contains the original and translated versions.

This project started at the 2023 R Project Sprint (see this issue for background) and is still experimental.

For users

Install this package:

pak::pak("eliocamp/rdlocal")

Next install a translation module. The base.es package hosts translations for base::mean() as an example, install it with:

pak::pak("eliocamp/base.es")

Setting the LANGAUGE environmental variable to “es” will change your R language.

library(rdlocal)
Sys.setenv(LANGUAGE = "es")

Now base::mean()’s help page will be displayed in Spanish.

For translators

First get a copy of the package you want to translate.

Choose your translation language by its ISO 2-letter code with a regional option using underscore. For example Spanish would be language = "es", and Argentine Spanish would be language = "es_AR".

Then use rdlocal::i18n_module_create() to create a lang translation module for that package

rdlocal::i18n_module_create(package_path = "path/to/package",
                            language = "lang", 
                            module_name = "package.lang", 
                            module_path = "path/to/module.lang", 
                            )

The translation strings are saved into yaml files, one per Rd file of the original package.

You can find them in path/to/module.lang/inst/translations with this format:

title:
  original: Title in the original language
  translation: ~

Where title is the section in the documentation, original stores the original string and translation will have the translated string.

Translation modules can be distributed and install from GitHub or R-Universe.

Known issues

  1. It’s not clear that the page is a translation and not the “official” one.
  2. It’s not possible to access the original documentation without changing the LANGUAGE environmental variable and opening the help page again.
  3. There are some formatting issues, such as the ... argument name.