The traduire R package provides a wrapper around the i18next JavaScript library. It presents an alternative interface to R’s built-in internationalisation functions, with a focus on the ability to change the target language within a session. Currently the package presents only a stripped down interface to the underlying library, though this may expand in future.

R’s built-in internationalisation is focussed on translating messages, warnings and errors transparently for package authors, within a session that does not change language. The translation is completely transparent, as one writes:

warning("spline: first and last y values differ - using y[1] for both")

(for example, in stats::spline), and the text used will vary depending on the locale (the environment variable LC_MESSAGES) to show, in a French locale:

Warning message:
In stats::spline(1:10, 1:10, method = "periodic") :
  spline : la première et la dernière valeurs de y diffèrent - y[1] utilisé pour les deux

It is harder to generate translations in contexts other than messages, warnings and errors - for example the axes of a plot, the output of a knitr document, or the results of a web service. It is also not straightforward to change the language of translation during a session (e.g., to produce knitr output in two different languages, or to respond to a query in a language that changes at the client’s request).

For this, we wanted the ability to internationalise strings on the fly, changing languages within a session, and decoupled from messages. When used within a package, the interface is lightweight.

For an introduction to the package, see the vignette, which shows how to internationalise strings, including strings requiring interpolation (substitution of variables), and for a more complete example that implements an internationalised “hello-world-as-a-service”, showing how to change languages dynamically.

Note that this package is designed only to help with tooling your package or application to allow it to be translated; the translations of content must still be carried out by hand.


Install with drat from our repository


Or, install directly from GitHub:



MIT © Imperial College of Science, Technology and Medicine