Set Default Language for WordPress Frontend and Admin Panel

Code

<?php
/**
 * Set different languages for WordPress frontend and admin panel.
 * 
 * This snippet allows you to set a default language for the frontend and a different language for the admin panel.
 * Ensure that the desired languages are installed in your WordPress setup.
 */

// Hook into 'locale' to change the language for the frontend
add_filter('locale', 'wp_dudecom_set_frontend_language');
function wp_dudecom_set_frontend_language($locale) {
    // Check if the current request is for the admin panel
    if (is_admin()) {
        return $locale; // Return the default locale for admin
    }

    // Set the desired locale for the frontend
    $frontend_locale = 'fr_FR'; // Change 'fr_FR' to your desired frontend language code

    return $frontend_locale;
}

// Hook into 'locale' to change the language for the admin panel
add_filter('locale', 'wp_dudecom_set_admin_language');
function wp_dudecom_set_admin_language($locale) {
    // Check if the current request is for the admin panel
    if (!is_admin()) {
        return $locale; // Return the default locale for frontend
    }

    // Set the desired locale for the admin panel
    $admin_locale = 'en_US'; // Change 'en_US' to your desired admin language code

    return $admin_locale;
}

// Ensure the languages are loaded
add_action('after_setup_theme', 'wp_dudecom_load_textdomain');
function wp_dudecom_load_textdomain() {
    load_theme_textdomain('your-text-domain', get_template_directory() . '/languages');
}
?>