admin/development: Add language management page

New in Mahara 22.04: You can install languages
in which the interface can be used  directly
in Mahara (Bug #1884717).

source/administration/development.rst

@@ -17,7 +17,7 @@ Development
 This administration section includes tools for developers to make them easily accessible.
 
 .. index::
-   single: Development; Behat steps
+   pair: Development; Behat steps
 
 .. _behat_steps:
 
@@ -42,7 +42,7 @@ On this page you see the Behat steps that you can use in Mahara out of the box.
 #. The line and the step are displayed.
 
 .. index::
-   single: Development; Components library
+   pair: Development; Components library
 
 .. _components_library:
 
@@ -64,7 +64,7 @@ Mahara uses a number of third-party plugins that deliver JavaScript, filtering,
 #. **URL**: Official URL of the plugin where you can find out more about it.
 
 .. index::
-   single: Site administrator; Embedded URLs
+   pair: Development; Embedded URLs
 
 .. _embedded_urls:
 
@@ -90,7 +90,45 @@ When you migrate your site to a different domain, content such as images embedde
    Use this tool instead of updating the URLs via a database query because text is stored serialised and can't be updated via a SQL query.
 
 .. index::
-   single: Development; Style guide
+   pair: Development; Languages
+
+.. _languages:
+
+|new in Mahara 22.04| Languages
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+*Administration menu → Development → Languages*
+
+You can install and update language packs on this page, keeping the translations of the interface up to date. This is handy if you know that changes have been made to a translation that you have, but you don't have direct server access. This automates the process of downloading the language from the `Mahara language pack site <https://langpacks.mahara.org/>`_.
+
+These languages are only for the translation of the interface. You can use any language that is supported by Unicode when you add text yourself as Mahara.
+
+.. note::
+   English is not listed here as that is the default language for Mahara. You can find the languages and how much they have been translated for the Mahara interface in the `translation project <https://translations.launchpad.net/mahara-lang/>`_.
+
+   If your desired language is not available, you can `start a translation <https://wiki.mahara.org/wiki/Developer_Area/Language_Packs>`_ for it.
+
+.. figure:: /images/administration/languages.*
+   :alt: Install and update languages for the interface
+
+   Install and update languages for the interface
+
+#. Select the language pack that you want to install from the drop-down menu and click the *Add language* button to add it to your site. The latest translations available for the version of Mahara you are using will be installed.
+#. Click the *All* button to select all languages mentioned on this page to be updated.
+#. Click the *None* button to revert your selection.
+#. You can select individual languages by ticking their checkbox.
+#. **Name**: The name of the language in its language.
+#. **Language code**: The international two-letter code by which the language is identified on the Mahara language pack site.
+#. **Last updated on**: The time when the language was last updated through this interface.
+
+   .. note::
+      If you install or update a language via a zip file or use the :ref:`language pack update CLI script <cli_langpacks>`, that is not tracked here.
+
+#. **File origin**: Link to the file on the Mahara language pack site.
+#. Click the *Update* button to pull the latest versions of the selected languages and install them.
+
+.. index::
+   pair: Development; Style guide
 
 .. _styleguide: