add id “selected” based on URL to wordpress language switcher

<?php if( is_front_page() || is_home() ) { ?>
<div class="motto_info_wrapper">
    <div class="motto">
    <h6>режиссёр-постановщик</h6>
    <h1>Kirill Zolotarev</h1>
    <ul>
        <li id="<?php if ( $_SERVER['REQUEST_URI'] == '/' ) { echo "selected"; }?>"><a class="russian_lang" href="<?php bloginfo('url'); ?>" title="">RUSSIAN</a></li>
        <li> | </li>
        <li id="<?php if ( $_SERVER['REQUEST_URI'] == '/en' ) { echo "selected"; }?>"><a class="english_lang" href="<?php bloginfo('url'); ?>/en/" title="">ENGLISH</a></li>
    </ul>
    <div id="blob"></div>
    </div>
</div>
<?php } ?>

Though it doesn’t work here mysite