diff --git a/reference/forms/types/language.rst b/reference/forms/types/language.rst
index b5482d9cdeb..9338f28096e 100644
--- a/reference/forms/types/language.rst
+++ b/reference/forms/types/language.rst
@@ -14,6 +14,7 @@ in the `International Components for Unicode`_ (e.g. ``fr`` or ``zh_Hant``).
 .. note::
 
    The locale of your user is guessed using :phpmethod:`Locale::getDefault`
+   Don't forget install 'intl' package PHP to have translation.
 
 Unlike the ``ChoiceType``, you don't need to specify a ``choices`` option as the
 field type automatically uses a large list of languages. You *can* specify the option