This document explains the processes of internationalization (i18n) and localization (l10n) in WordPress, including the use of gettext libraries for translation. It details how to implement localization in WordPress themes and plugins, the types of files involved (POT, PO, MO), and various functions used for translating text messages. Additionally, it covers tools like Poedit for managing translations and provides examples for coding and configuring translations in WordPress.

1. By
Md. Sajedul Haque Romi
Email: romi@codebangla.com

2. • Understanding Internationalization
& localization
• Tools for localization
•Implementation localization in WP
themes
•Implementation localization in WP
plugins

3. Internationalization is the process of
designing a software application so that it
can be adapted to various languages and
regions without engineering changes.

4. Localization is the process of adapting
internationalized software for a specific
region or language by adding locale-
specific components and translating text.

5. WordPress uses the gettext libraries
and tools for i18n.
In WordPress, you should use the
__() wordpress-defined PHP gettext-
compliant translation function.

6. There are three types of files used in the
gettext translation framework.
•POT (Portable Object Template) files
•PO (Portable Object) files
•MO (Machine Object) files

7. In your theme or plugin PHP files, write
codes in the following way.
__('message') passes the translation
to the PHP return statement.
_e('message') passes the translation
to the PHP echo statement.
Example:
<?php
$translated_text = __( 'text', 'domain' );
?>
Domain: Unique identifier for retrieving
translated strings

8. •Load a text domain
•Process text messages with WordPress
functions
•Extract these messages with the appropriate
software
•Provide a translation for each message
•Create a language file for a particular locale
•Instruct WordPress to enable localization and to
load the language file

9. For Theme:
In wp-content/themes/Test-Theme/functions.php
For Plugin:
In wp-content/plugins/Test-Plugin/index.php

10. echo "Hello user";
_e("Hello user","mytheme");
the_content( "Read more" );
the_content( __("Read more","mytheme")
);

11. Sometimes, a text message includes
dynamic data, such as a number from a
PHP variable. In this case, we use the
sprintf() function to produce the final
message string:
$results_found = 12;
$message = sprintf( __("%s results found"
, "mytheme") , $results_found );

12. WordPress provides a function for singular
and plural translation of the same text
message called _n():
_n( $single, $plural, $number, $domain );

13. Though the _n() is a built in WordPress function, using it is discouraged because
the translation software parses only the first parameter of a function, and so
these two text messages would not be fetched. Instead, we can use the PHP if
statement:
if($results_found == 1)
$message = __("1 result found" , "my-text-
domain");
else
$message = sprintf( __("%s results found" , "my-
text-domain") , $results_found );

14. WordPress provides date_i18n() to
translate dates.
Example:
<?php
echo date_i18n(get_option('date_format')
,strtotime("11/15-1976"));
?>
http://codex.wordpress.org/Function_Reference/date_i18n
Bangla date translation
http://tareq.wedevs.com/2010/09/translate-wordpress-date-time-comment-number-to-bangla-digit/

15. _x()
_ex()
_nx()
_n()
esc_html()
esc_attr()
esc_attr__()
esc_attr_e()
esc_js()
esc_textarea()
esc_url()

18. •Poedit
•GlotPress
•GNU gettext
Among them, Poedit is widely used for
WordPress I18n & l10n. So we will be
focused on Poedit translation method.

20. Go to File>New Catalog…

23. Click ok, if you add the path correctly, you
should see something like this

24. Save the file as .pot ( not default.po)
For theme ex: languages/test-theme.pot
For plugin ex: languages/test-plugin.pot
Then in Poedit, go to File>New catalog
from POT file… you will see your template
for translation

25. Some thing like this

26. See the Source text box
Add your translated phrase in
Translation box

27. When you are done adding your translated phrases, save the file in
the WordPress
theme as en_US.po or your language code
.po file like bn_BD.po
For plugin
must save your-plugin-en_US.po
Ex: test-plugin-bn_BD.po
When you save the .po file a .mo file will be generated.

28. Open wp-config.php file search for
define('WPLANG’
Add your lanuage code and save it

30. Congratulation!
You have successfully finished your
WordPress Theme & Plugin Translations.

31. Reference:
http://codex.wordpress.org/Translating_WordPress
http://wp.smashingmagazine.com/2011/12/29/internationalizing-
localizing-wordpress-theme/

32. Md. Sajedul Haque Romi
Founder & CEO
CodeBANGLA
Email: romi@codebangla.com