There are some fantastic multilingual plugins for WordPress, however for one client project I needed something far more flexible, as this particular client needed to cater for several countries that each spoke several languages.
In short the client needed to be able to have a multisite instance that had a country and language set as default, and the ability to override the country and language on each page / post.
Building a Multilingual Plugin
If enough people bug me to do it, I may consider releasing the whole thing as a standalone plugin, however the heart of the multilingual plugin I build relies on the locale WordPress filter, and the heart of the plugin resides in the following code snippet:
/**
* Redefine the sites Locale (site langauge)
*
* In this example we try to get the country and the langauge from the page meta,
* if that doesnt exist we fallback to the country and langauge set in the customizer,
* which in turn fall back to gb and en.
*/
function mwtsn_example_redefine_locale( $locale ) {
$country = get_post_meta( get_the_id(), '_mwtsn_example_global_country_override', true );
$lang = get_post_meta( get_the_id(), '_mwtsn_example_global_language_override', true );
if ( ( empty( $lang ) || ! ( is_page() || is_single() || is_singular() ) ) ) {
$country = get_theme_mod( 'mwtsn_example_multilingual_country', 'gb' );
$lang = get_theme_mod( 'mwtsn_example_multilingual_language', 'en' );
}
if ( 'default' !== $country ) {
$locale = $lang . '_' . strtoupper( $country );
} else {
$locale = $lang . '-' . $country;
}
return $locale;
}
add_filter( 'locale', 'mwtsn_example_redefine_locale', 10 );Tada! Your locale is now set, and your multilingual site should now be switching languages based on your page/site meta.
Wait! My WordPress Core Default Translations Are Not Working!
This is an issue I came across, and couldn’t for the life of me figure it out. My theme translated perfectly after I had added the relevant .mo and .po files, however WordPress core default translations (such as the ‘Leave a Reply’ message in the comments template) were not translating.
It turns out the solution was pretty simple! Although I had catered for custom domain translations, I had forgot to put one simple bit of code into my theme: load_default_textdomain().
/** * Load default text domain * * If default WordPress Core translations don't work, add this to your * `functions.php` file. */ load_default_textdomain();
If I have shaved a couple of hours off of your debugging with that ‘one weird tip’, you are welcome!