diff --git a/README.md b/README.md
index 713090e..48c34aa 100644
--- a/README.md
+++ b/README.md
@@ -143,6 +143,11 @@ You can configure the client (the JS part) via `data-` attributes:
     <script src="..." data-isso-css="false"></script>
     ```
 
+*   data-isso-lang
+
+    Override useragent's preferred language. Currently available: german (de),
+    english (en) and french (fr).
+
 *   data-isso-reply-to-self
 
     Set to `true` when spam guard is configured with `reply-to-self = true`.
diff --git a/isso/js/app/config.js b/isso/js/app/config.js
index d946857..1456c40 100644
--- a/isso/js/app/config.js
+++ b/isso/js/app/config.js
@@ -3,6 +3,7 @@ define(function() {
 
     var config = {
         "css": true,
+        "lang": (navigator.language || navigator.userLanguage).split("-")[0],
         "reply-to-self": false
     };
 
diff --git a/isso/js/app/i18n.js b/isso/js/app/i18n.js
index 83ec30d..17090bc 100644
--- a/isso/js/app/i18n.js
+++ b/isso/js/app/i18n.js
@@ -11,8 +11,8 @@ define(["app/i18n/de", "app/i18n/en"], function(de, en) {
 
     plurals["de"] = plurals["en"];
 
-    // the user's language. you can replace this with your own code
-    var lang = (navigator.language || navigator.userLanguage).split("-")[0];
+    // useragent's prefered language (or manually overridden)
+    var lang = config.lang;
 
     // fall back to English
     if (!plurals[lang]) {