TMNR on "[Plugin: Polylang] Using pll_the_languages(); in Twenty Eleven child theme"

I've read all available threads on this issue. Still can't get it to run. Now tell me if i'm wrong, but to test this function i've tried to add
<ul><?php pll_the_languages(); ?></ul> one of my pages content area in HTML mode (via WordPress dashboard). Also tried the same line in header.php, i mentioned previously - it breaks the CSS. Unfortunately no link 'cause i'm on a local dev server.