Function extending with if query in functions.php

may be it’s clearer like this :

add_filter('wpseo_set_title', function ($title) {


    if (is_single()) {

        $page_comment = get_query_var('cpage');

        if ($page_comment > 3) {

            $title = "Kontroverse Diskussionen zu: $page_comment $title";

        } elseif ($page_comment > 0) {

            $title = "Meinungen zu: $page_comment $title";

        }

    }


    return $title;

});