function remove_all_language_switcher_metaboxes() {
    global $wp_meta_boxes;
    if (isset($wp_meta_boxes['nav-menus']['side'])) {
        foreach ($wp_meta_boxes['nav-menus']['side'] as &$context) {
            foreach ($context as &$priority) {
                foreach ($priority as $id => &$box) {
                    if (strpos($id, 'lang') !== false || strpos($id, 'language') !== false) {
                        unset($priority[$id]);
                    }
                }
            }
        }
    }
}
add_action('admin_menu', 'remove_all_language_switcher_metaboxes', 999);<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="https://kjunion8.com/wp-sitemap-index.xsl" ?>
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"><sitemap><loc>https://kjunion8.com/wp-sitemap-posts-post-1.xml</loc></sitemap><sitemap><loc>https://kjunion8.com/wp-sitemap-posts-page-1.xml</loc></sitemap><sitemap><loc>https://kjunion8.com/wp-sitemap-posts-product-1.xml</loc></sitemap><sitemap><loc>https://kjunion8.com/wp-sitemap-posts-tahefobu_header-1.xml</loc></sitemap><sitemap><loc>https://kjunion8.com/wp-sitemap-taxonomies-category-1.xml</loc></sitemap><sitemap><loc>https://kjunion8.com/wp-sitemap-taxonomies-product_brand-1.xml</loc></sitemap><sitemap><loc>https://kjunion8.com/wp-sitemap-taxonomies-product_cat-1.xml</loc></sitemap><sitemap><loc>https://kjunion8.com/wp-sitemap-taxonomies-product_tag-1.xml</loc></sitemap><sitemap><loc>https://kjunion8.com/wp-sitemap-users-1.xml</loc></sitemap></sitemapindex>