load_theme_textdomain() WordPress Function

The load_theme_textdomain() function loads a plugin or theme's translated .mo file. This function should be called after the theme's or plugin's textdomain is loaded. For example, if a theme's textdomain is "my-theme", it would call load_theme_textdomain( 'my-theme', get_template_directory() . '/languages' ); to load its translations. This function can be used to load a theme's or plugin's translations when the textdomain is not known. For example, if a theme is using a textdomain that is not yet registered, it can call load_theme_textdomain() with the path to its translations: load_theme_textdomain( 'my-theme', get_template_directory() . '/languages' );

load_theme_textdomain( string $domain, string|false $path = false ) #

function load_theme_textdomain( $domain, $path = false ) {
	/**
	 * Filters a theme's locale.
	 *
	 * @since 3.0.0
	 *
	 * @param string $locale The theme's current locale.
	 * @param string $domain Text domain. Unique identifier for retrieving translated strings.
	 */
	$locale = apply_filters( 'theme_locale', determine_locale(), $domain );

	$mofile = $domain . '-' . $locale . '.mo';

	// Try to load from the languages directory first.
	if ( load_textdomain( $domain, WP_LANG_DIR . '/themes/' . $mofile ) ) {
		return true;
	}

	if ( ! $path ) {
		$path = get_template_directory();
	}

	return load_textdomain( $domain, $path . '/' . $locale . '.mo' );
}