How to Make Multilingual Plugins and Themes

John P Bloch ● 2015-09-12 ● WordCamp DFW

About MeJohn P Bloch

Lead Web Engineer at 10up

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DFW Local (Irving)

Definitions

Definitions

Internationalization

The process of making your code translatable at all.

Abbreviated as i18n

Localization

The process of using translated text in internationalized code.

Abbreviated as l10n

Definitions

Internationalization

The process of making your code translatable at all.

Abbreviated as i18n

Localization

The process of using translated text in internationalized code.

Abbreviated as l10n

Why

Why

• Empathy• Grow your potential user-base• Potentially make more money• Make more of an impact in the world

How

How translation works in WordPress

English text goes into a translation functionWP looks for translations of the text in the current languageIf a translation is found, the function uses thatOtherwise it uses the English text

Text Domains

A text domain is a namespace for your code’s translations

If you use the wordpress.org repositories, you must use your plugin or theme’s slug as the text domain

Even if you’re not on the official repos it’s still a good idea

Text Domains – Loading

Pluginsload_plugin_textdomain()Run on plugins_loaded actionArguments• The text domain• false // deprecated• Location of translations

• Relative to plugins directory

Themesload_theme_textdomain()Run on after_setup_themeArguments• The text domain• Location of translations

• Absolute path

Plugin and Theme Headers

Plugins and themes have two special headers:

Text DomainDomain Path

Basic Translation Functions

__()

Basic Translation Functions

__()_e()

Basic Translation Functions

__()_e()_n()

Basic Translation Functions

__()_e()_n()

_x()_ex()_nx()

Basic Translation Functions

You can leave longer comments for the translators

Advanced Translation Functions

number_format_i18n()

Advanced Translation Functions

number_format_i18n()date_i18n()

Advanced Translation Functions

number_format_i18n()date_i18n()wp_localize_script()

For adding translated strings to javascriptTranslates text in PHP and outputs as a global javascript variable

wp_localize_script()

wp_localize_script()

wp_localize_script()

Final Steps

Final Steps

• Generate .pot file• Official repositories provide web tools• Generate locally with PoEdit or makepot.php

• Publish .pot file• Usually packaged with plugin or theme in the languages directory

• Add translation files to your plugin or theme

Gotchas

• Line breaks• Empty strings• Formatted strings vs. interpolation

_e( "You live in $state", 'my-plugin' );

_e( "You live in $state", 'my-plugin' );

printf( __( 'You live in %s', 'my-plugin' ), $state );

printf( __( 'Hi %s, you live in %s', 'my-plugin' ), $user_name, $state);

printf( __( 'Hi %s, you live in %s', 'my-plugin' ), $user_name, $state);

printf( __( 'Hi %s, you live in %s', 'my-plugin' ), $user_name, $state);

printf( __( 'Hi %1$s, you live in %2$s', 'my-plugin' ), $user_name, $state);

Best Practices

Best Practices

• Use decent English style• Avoid slang and abbreviations

• Keep text together• Break at paragraphs• Use formatted strings instead of

concatenation• Translate phrases not words

Best Practices

Bad:echo __( 'Click ', 'my-plugin' ) . '<a href="/there">' . __( 'here', 'my-plugin' ) . '</a>' . __( ' for stuff.', 'my-plugin' );

Better:_e( 'Click <a href="/there">here</a> for stuff.', 'my-plugin' );

Best Practices

Best:echo '<a href="/there">' . __( 'Click here for stuff.', 'my-plugin' ) . '</a>';

Best Practices

Bad:echo __( 'Thanks for using ', 'my-plugin' ) . 'My Plugin!';

Better:echo sprintf( __( 'Thanks for using %s', 'my-plugin' ), 'My Plugin' ) . '!';

Best:printf( __( 'Thanks for using %s!', 'my-plugin' ), 'My Plugin' );

Best Practices

• Use decent English style• Avoid slang and abbreviations

• Keep text together• Break at paragraphs• Use formatted strings instead of

concatenation• Translate phrases not words

• No unnecessary HTML

• Make no assumptions about the translated text

• Length• Word order• Direction• Punctuation

• Avoid translating URLs that don’t have alternate languages available

Tools

• Pig Latin (http://w.org/plugins/piglatin/)• WP i18n Tools (develop.svn.wordpress.org/trunk/tools/i18n/)• PoEdit (https://poedit.net/)• GlotPress (http://blog.glotpress.org/)• Language Packs

Questions?Twitter: @johnpbloch

Website: https://johnpbloch.comEmail: john.bloch@10up.com