Merge pull request #3361 from jim-parry/userguide/language
Enhance Language Class Writeup in User Guide (closes #674)
diff --git a/user_guide_src/source/index.rst b/user_guide_src/source/index.rst
index 09bf770..56ce619 100644
--- a/user_guide_src/source/index.rst
+++ b/user_guide_src/source/index.rst
@@ -72,14 +72,15 @@
libraries/index
-****************
-Driver Reference
-****************
+******************
+Database Reference
+******************
-- :doc:`libraries/caching`
-- :doc:`database/index`
-- :doc:`libraries/javascript`
-- :doc:`libraries/sessions`
+.. toctree::
+ :glob:
+ :titlesonly:
+
+ database/index
****************
Helper Reference
diff --git a/user_guide_src/source/libraries/language.rst b/user_guide_src/source/libraries/language.rst
index 6949c11..c3f9b6d 100644
--- a/user_guide_src/source/libraries/language.rst
+++ b/user_guide_src/source/libraries/language.rst
@@ -5,14 +5,24 @@
The Language Class provides functions to retrieve language files and
lines of text for purposes of internationalization.
-In your CodeIgniter system folder you'll find one called language
-containing sets of language files. You can create your own language
-files as needed in order to display error and other messages in other
-languages.
+In your CodeIgniter **system** folder, you will find a **language**
+subfolder containing a set of language files for the **english** idiom.
+The files in this folder (**system/language/english/**) define the regular messages,
+error messages, and other generally output terms or expressions, for the different parts
+of the CodeIgniter core framework.
-Language files are typically stored in your **system/language/** directory.
-Alternately you can create a directory called language inside your
-application folder and store them there. CodeIgniter will always load the
+You can create or incorporate your own language
+files, as needed, in order to provide application-specific error and other messages,
+or to provide translations of the core messages into other languages.
+These translations or additional messages would go inside your application/language folder,
+with separate subfolders for each idiom (for instance french or german).
+
+The CodeIgniter framework comes with a set of language files for the "english" idiom.
+Additional approved translations for different idioms may be found in the
+`CodeIgniter 3 Translations repositories <https://github.com/codeigniter3-translations>`_.
+Each repository deals with a single idiom.
+
+When CodeIgniter loads language files, it will load the
one in **system/language/** first and will then look for an override in
your **application/language/** directory.
@@ -26,6 +36,70 @@
<div class="custom-index container"></div>
+***************************
+Handling Multiple Languages
+***************************
+
+If you want to support multiple languages in your application, you would provide folders inside
+your **application/language/** directory for each of them, and you would specify the default
+language in your **application/config/config.php**.
+
+The **application/language/english/** directory would contain any additional language files
+needed by your application, for instance for error messages.
+
+Each of the other idiom-specific directories would contain the core language files that you
+obtained from the translations repositories, or that you translated yourself, as well as
+any additional ones needed by your application.
+
+You would store the language you are currently using, for instance in a session variable.
+
+Sample Language Files
+=====================
+
+::
+
+ system/
+ language/
+ english/
+ ...
+ email_lang.php
+ form_validation_lang.php
+ ...
+
+ application/
+ language/
+ english/
+ error_messages_lang.php
+ french/
+ ...
+ email_lang.php
+ error_messages_lang.php
+ form_validation_lang.php
+ ...
+
+Example of switching languages
+==============================
+
+::
+
+ $idiom = $this->session->get_userdata('language');
+ $this->lang->load('error_messages',$idiom);
+ $oops = $this->lang->line('nessage_key');
+
+********************
+Internationalization
+********************
+
+The Language class in CodeIgniter is meant to provide an easy and lightweight way to support multiple
+languages in your application. It is not meant to be a full implementation of what is commonly called
+`internationalization and localization <http://en.wikipedia.org/wiki/Internationalization_and_localization>`_.
+
+We use the term "idiom" to refer to a language using its common name,
+rather than using any of the international standards, such as "en", "en-US", or "en-CA-x-ca" for English
+and some of its variants.
+
+.. note:: There is nothing to prevent you from using those abbreviations in your application!
+
************************
Using the Language Class
************************