This document covers the concepts of internationalization (i18n), localization (l10n), and multilingual support in WordPress, detailing their definitions and implementation methods. It provides examples of best practices for coding themes and plugins to support translation and the use of associated file types like .pot, .po, and .mo. Additionally, it discusses common issues encountered with multilingual setup and offers useful resources for further guidance.

1. WordPress
- Internationalization
- Localization
- Multilingual
(April 16, 2016)
Do
It
Right

2. Me and Company
Dat Hoang
Community & Support at OnTheGoSystems
Image credit: Denise VanDeCruze - OnTheGoSystems.

3. Me and Company
OnTheGoSystems
wp-types.comwpml.org icanlocalize.com

4. Main Content
● What are they?
● Internationalization
● Localization
● Multilingual (with WPML)

5. What are They?
Internationalization (i18n) is the process of
developing your theme/plugin language, so it can
easily be translated into other languages.
Localization (l10n) describes the subsequent
process of translating an internationalized
theme/plugin.
Multilingual means there are more than one
language in sites.

6. Internationalization (1)
Wrong
echo 'WordPress is the best!';
Right (use gettext functions)
echo __( 'WordPress is the best!', 'my-text-domain' );
Wrong (don’t be clever!)
__( 'Translate me.' , $my_text_domain );
Right (no variable, constant… for text domains)
__( 'Translate me.' , 'my-text-domain' );

7. Internationalization (2)
Basic functions:
● __(), _e()
● _x(), _ex() - Disambiguation by context
_x( 'Post', 'noun', 'my-text-domain' );
_x( 'Post', 'verb', 'my-text-domain' );
● _n(), _nx() - Plural/singular nouns
sprintf(
_n( '%s star', '%s stars', $rating, 'text-domain' ),
$rating );
● _n_noop(), _nx_noop(), translate_nooped_plural()

8. Internationalization (3) - JavaScript
function add_my_script() {
// Register the script
wp_register_script( 'some_handle',
get_template_directory_uri() . '/custom.js' );
// Localize the script with new data
$translation_array = array (
'some_string' => __( 'Some string to translate',
'text-domain' ),
'a_value' => '10'
);
wp_localize_script( 'some_handle', 'object_name',
$translation_array );
// Enqueued script with localized data.
wp_enqueue_script( 'some_handle' );
}
add_action( 'wp_enqueue_scripts', 'add_my_script' );

9. Internationalization (4) - JavaScript
custom.js
<script>
// alerts 'Some string to translate'
alert( object_name.some_string);
</script>
HTML:
<script type='text/javascript'>
/* <![CDATA[ */
var object_name = {"some_string":"Some string to
translate","a_value":"10"};
/* ]]> */
</script>

10. Internationalization (5)
Date and number functions:
- number_format_i18n()
- date_i18n()
Escape functions:
esc_html__()
esc_html_e()
esc_html_x()
esc_attr__()
esc_attr_e()
esc_attr_x()

11. Internationalization (6)
Load .mo files:
function my_plugin_load_plugin_textdomain() {
load_plugin_textdomain( 'text-domain', FALSE,
basename( dirname( __FILE__ ) ) . '/languages/' );
}
add_action( 'plugins_loaded',
'my_plugin_load_plugin_textdomain' );
Last but not least: original language = ENGLISH

12. Localization (1)
File Types
● POT (Portable Object Template)
#: plugin-name.php:123
msgid "Page Title"
msgstr ""
● PO (Portable Object)
● MO (Machine Object)

13. Localization (2)
Generates POT / PO / MO files
● Plugin Repository Admin Tools
● WordPress i18n tools
● Grunt
● WPML String Translation
● MO files:
○ msgfmt -o filename.mo filename.po
○ Online tools
○ grunt-po2mo

14. Localization (3)
Translate
● Poedit
● Plugins:
○ Loco Translate
○ WPML String Translation
● Google Translator Toolkit
● translate.wordpress.org

15. Localization (4)
Feel localization!
● Settings > General > Site language
● Put the correct folders
○ wp-content/languages/plugins/text-domain-vi_VN.mo
○ wp-content/plugins/my-plugin/languages/text-domain-vi_VN.mo

16. Localization (5)
Contribute: Everyone can help
● https://wpvi.wordpress.com/
● https://translate.wordpress.
org/locale/vi/default/wp/dev
● https://translate.wordpress.org/projects/wp-
plugins/woocommerce

17. Multilingual (with WPML)
● Gettext strings
● Options (saved in wp_options)
● Content (posts, categories, menus)
● WooCommerce
● Common issues

18. Multilingual (1)
Gettext strings
● Important: theme and plugins are ready for
internalization/localization.
● Use .mo files
● Use WPML > String Translation

19. Multilingual (2)
Options - translate in WPML String Translation
● Automatically: wpml-config.xml
● Manually: adding strings in wp-admin

20. Multilingual (3)
Content - posts

21. Multilingual (4)
Content - categories

22. Multilingual (5)
Content - menus

23. Multilingual (6)
WooCommerce - install WCML

24. Multilingual (7)
Common issues:
● Translate custom strings
- wpml_register_single_string
- wpml_translate_single_string
● wp_query($args) or get_posts($args) doesn’t
filter out correct posts IDs for the current
language
- add "suppress_filters=0" to arguments.

25. Multilingual (8)
Common issues:
● A custom post is different in a second
language
$post = get_post(
apply_filters( 'wpml_object_id', $post->ID, 'cpt' ) );
● A custom taxonomy ID is different in a second
language
$tax_id =
apply_filters( 'wpml_object_id', $tax_id, 'tax' );

26. Discussion
Image credit: http://sweetclipart.com/diverse-people-raising-hands-968

27. Useful Links
1. https://developer.wordpress.
org/plugins/internationalization/localization
2. https://developer.wordpress.
org/plugin/internationalization/how-to-internationalize-your-
plugin
3. https://docs.woothemes.com/document/woocommerce-
localization/
4. https://wpml.org/documentation/related-
projects/woocommerce-multilingual/
5. https://wpml.org/documentation/support/debugging-theme-
compatibility/
6. https://wpml.org/documentation/translating-your-contents/

28. Big Thanks!
Dat Hoang
Community & Support
E: dat.h@icanlocalize.com
W: wpml.org | wp-types.com | icanlocalize.com
Saigon, April 16, 2016