Multilingual Documentation in R Packages

We are happy to announce the brand-new R Consortium Multilingual Working Group. This Working Group came about after discussions during the R Project Sprint 2023 and will oversee the implementation of multilingual documentation support in R and organise community translation efforts. Our first project is the (experimental) rhelpi18n package, which adds multilingual documentation support!

Do you want to read the documentation for base::mean() (partially) in Spanish? Install the experimental rhelpi18n package and the sample translation module base.es:

# install.packages("pak")
pak::pak(c("eliocamp/rhelpi18n", "eliocamp/base.es"))

And then run this code:

library(rhelpi18n)
Sys.setenv(LANGUAGE = "es")
help(mean)

Media Aritmética
Description:
Función genérica para la media aritmética (recortada)
Usage:
mean(x, ...)
## Default S3 method:
mean(x, trim = 0, na.rm = FALSE, ...)
Arguments:
x: an R object. Currently there are methods for numeric/logical
vectors and date, date-time and time interval objects.
Complex vectors are allowed for 'trim = 0', only.
trim: la fracción (0 a 0.5) de observaciones para ser recordatas
del final de \codex antes de computar la media. Valores de
trim pro fuera de ese rango se consideran al punto más
cercano.
na.rm: un valor lógico que evalua a 'TRUE' o 'FALSE' indicando si
valores 'NA' deben ser removidos antes de realizar el
cómputo.
...: further arguments passed to or from other methods.
... (27 more lines)

Nice! This should work on any R console or IDE.

Why would you do this?

Although English is the de facto international language, there are benefits to including resources in different languages. By reducing language barriers we end up with a larger, stronger, more creative community with more ideas and resources. The English hegemony is reflected in R by the use of English in its documentation, such as manual pages, function names, and argument names (why use mean() instead of Mittelwert()?).

Package documentation can be written in any language, and CRAN supports non-English documentation by using the “Language” field¹. But still, the vast majority of packages are documented in English and there is only a small number of packages documented in other languages are seemingly tailored to their target audience. For example, the labstatR package serves as a companion to the Italian book “Laboratorio Di Statistica Con R” and is partially documented in Italian (it uses English function names and arguments). Similarly, chilemapas provides simplified maps for Chile, with full Spanish documentation, including function names. rOpenSci’s own censo2017 by Mauricio Vargas is also fully documented in Spanish.

Although these packages are more accessible to their primary audience, they are much less accessible to the wider community. Users who do not speak the language may find it difficult to discover and use the functions that these packages provide. Package authors face the dilemma of either making their package inaccessible to their target demographic or isolating it from the wider R ecosystem.

This is a difficult problem without easy solutions. It comes up periodically in the rOpenSci Slack as well as in other R spaces, such as Stack Overflow. The developer of the utilsIPEA package expressed the need for bilingual documentation, recognising that his package would be used both by people in Brazil, who might prefer documentation in Portuguese, and the broader international community. At least two package developers have tried to solve this dilemma by documenting their package in English and publishing a second version documented in another language: ExpDes and ExpDes.pt, as well as orloca and orloca.es. The karel package, on the other hand, has two sets of functions, one with English names and documentation, and another in Spanish.

Both are workarounds that push the limits of what the R programming language can do in terms of multilingual functionality. Further, because these solutions are not native, they can become hard to maintain and don’t scale well.

That is why we are presenting the experimental rhelpi18n² package. This package is a test-bed for implementing seamless support for multilingual documentation with the aim of integrating it into R itself once it matures. A user can load rhelpi18n, install translation modules created by the community, and read R documentation in their language of choice.

OK, but how?

In our example above, translated strings are hosted in base.es, a translation module. This is a regular package with special fields in the DESCRIPTION specifying which package and version is being translated and to which language. Currently, translated strings are implemented as a list with the original string and the translation of each section in the documentation, but we are also looking at implementing this with traditional .po files, which is the mechanism used by R to translate messages and errors.

The rhelpi18n package modifies utils:::.getHelpFile(), which all help functions use to fetch documentation strings. It adds a few lines of code which check for relevant translation modules (such as base.es) and replaces the original strings with the translated strings on the fly.

In addition to presenting translated documentation, rhelpi18n also provides tools for developers to create new translation modules.

For example, the following code creates a basic translation module for the glue package, including all the functionality and strings that need translating.

dir <- file.path(tempdir(), "glue.es")
rhelpi18n::i18n_module_create(module_name = "glue.es",
 package_path = glue_dir, # Path to local copy of glue source code
 language = "es",
 module_path = dir)

Now the heavy work is to go to the “translations” subdirectory and translate all the strings saved (currently) as YAML files. For example, the translation file for glue::as_glue() is:

title:
original: Coerce object to glue
translation: ~
arguments:
x:
original: object to be coerced.
translation: ~
'...':
original: further arguments passed to methods.
translation: ~
value:
original: |
A character vector with S3 class \code{"glue"}.
translation: ~
description:
original: |
A glue object is a character vector with S3 class \code{"glue"}. The \code{"glue"}
class implements a print method that shows the literal contents (rather than
the string implementation) and a \code{+} method, so that you can concatenate with
the addition operator.
... (16 more lines)

A possible (and superficial) translation would be

title:
original: Coerce object to glue
translation: Convertir un objeto a glue
arguments:
x:
original: object to be coerced.
translation: objeto a convertir.
'...':
original: further arguments passed to methods.
translation: otros argumentos que se pasan a los métodos.
value:
original: |
A character vector with S3 class \code{"glue"}.
translation: |
Vector de caracter con la clase S3 \code{"glue"}.
description:
original: |
A glue object is a character vector with S3 class \code{"glue"}. The \code{"glue"}
class implements a print method that shows the literal contents (rather than
the string implementation) and a \code{+} method, so that you can concatenate with
the addition operator.
translation: |
Un objeto glue es un vector de caracteres con la clase S3 \code{"glue"}.
La clase \code{"glue"} implementa un método de impresión que muestra los contenidos
literales (en vez de la implementación como cadena de caracteres) y un método \code{+}
para que puedas concatenar usando el operador de sumatoria.
examples:
original: |
x <- as_glue(c("abc", "\"\\\\", "\n"))
x
... (11 more lines)

After modifying “as_glue.yaml” and installing the package, now the documentation is in Spanish 🎉.

library(glue)
help(as_glue)

Convertir un objeto a glue
Description:
Un objeto glue es un vector de caracteres con la clase S3
'"glue"'. La clase '"glue"' implementa un método de impresión que
muestra los contenidos literales (en vez de la implementación como
cadena de caracteres) y un método '+' para que puedas concatenar
usando el operador de sumatoria.
Usage:
as_glue(x, ...)
Arguments:
x: objeto a convertir.
...: otros argumentos que se pasan a los métodos.
... (13 more lines)

Amazing!

Next steps

This is all in the early stages but things are moving fast. We are still experimenting with various ways to store translations and implement string replacements. It also has several limitations, such as not translating section headings yet. We also want to add a clear indication that the text is a translation and a convenient way of quickly accessing the original version. Part of the translations workflow often involves automated translations which are later reviewed by a human. So we are also considering adding metadata to strings to flag cases of automatic translations that haven’t been reviewed by a human or translations that might be slightly outdated (it would be a shame to not show a translation because someone fixed a small typo in the original text and it had yet to be reviewed!).

If you want to test the package and report any problems, or you have ideas on how to improve it, you can join the discussion by checking the open issues of the package and by joining the Multilingual Documentation Working Group. Come help us!