diff --git a/README.Rmd b/README.Rmd
index dd8c555..3e25e6a 100644
--- a/README.Rmd
+++ b/README.Rmd
@@ -12,7 +12,7 @@ knitr::opts_chunk$set(
   fig.path = "man/figures/README-",
   out.width = NULL
 )
-Sys.setlocale("LC_MESSAGES", 'en_GB.UTF-8') # Force locale
+Sys.setenv(LANGUAGE = "en") # Force locale
 ```
 
 # aion <img width=120px src="man/figures/logo.png" align="right" />
@@ -114,6 +114,16 @@ Y <- intervals(
 plot(x = Y)
 ```
 
+## Translation
+
+This package provides translations of user-facing communications, like messages, warnings and errors, and graphical elements (axis labels). You can use a specific language by setting the `LANGUAGE` environment variable (you only need to do this once per session):
+
+``` r
+Sys.setenv(LANGUAGE = "<language code>")
+```
+
+Languages currently available are English (`en`) and French (`fr`).
+
 ## Related Works
 
 * [**era**](https://github.com/joeroe/era) provides a consistent representation of year-based time scales as a numeric vector with an associated era.
diff --git a/README.md b/README.md
index 29847e0..318be99 100644
--- a/README.md
+++ b/README.md
@@ -144,6 +144,19 @@ plot(x = Y)
 
 ![](man/figures/README-time-intervals-1.png)<!-- -->
 
+## Translation
+
+This package provides translations of user-facing communications, like
+messages, warnings and errors, and graphical elements (axis labels). You
+can use a specific language by setting the `LANGUAGE` environment
+variable (you only need to do this once per session):
+
+``` r
+Sys.setenv(LANGUAGE = "<language code>")
+```
+
+Languages currently available are English (`en`) and French (`fr`).
+
 ## Related Works
 
 - [**era**](https://github.com/joeroe/era) provides a consistent