polylang-lang-list

    // Template tag: Displays links to the current page in other languages
    // Usage: do_action('the_languages');
    function the_languages($args = '') {
        $defaults = array(
            'dropdown' => 0, // display as list and not as dropdown
            'show_names' => 1, // show language names
            'show_flags' => 0, // don't show flags
            'hide_if_empty' => 1 // hides languages with no posts (or pages)
        );

        extract(wp_parse_args($args, $defaults));

        $listlanguages = $this->get_languages_list($hide_if_empty);
        $output = $dropdown ? '<select name="lang_choice" id="lang_choice" onchange="window.location.href=this.options[this.selectedIndex].value">' : "<ul>\n";
        foreach ($listlanguages as $language) {
            $url = $this->get_translation_url($language);
            $url = isset($url) ? $url : $this->get_home_url($language); // if the page is not translated, link to the home page

            $class = 'lang-item lang-item-'.esc_attr($language->term_id);
            if ($language->slug == $this->curlang->slug)
                $class .= ' current-lang';

            $flag = $show_flags &&
                file_exists(POLYLANG_DIR.($file = '/local_flags/'.$language->description.'.png')) ||
                file_exists(POLYLANG_DIR.($file = '/flags/'.$language->description.'.png')) ?
                '<img src="'.WP_PLUGIN_URL.'/polylang'.$file.'" alt="'.$language->name.'" />' : '';

            $name = $show_names || !$show_flags ? esc_attr($language->name) : '';

            $output .= $dropdown ?
                sprintf(
                    "<option value='%s'%s>%s</option>\n",
                    $url,
                    $language->slug == $this->curlang->slug ? ' selected="selected"' : '',
                    $name // FIXME flag does not work for the dropdown list
                ) :
                '<li class="'.$class.'"><a href="'.$url.'">'.($show_flags && $show_names ? $flag.'&nbsp;'.$name : $name)."</a></li>\n";
        }
        $output .= $dropdown ? '</select>' : "</ul>\n";
        echo $output;
    }