code: public function languageFallback()
  	{
  		$arrRoots = array();
  		$time = Date::floorToMinute();
  		$objRoots = $this->Database->execute("SELECT fallback, dns FROM tl_page WHERE type='root' AND (start='' OR start<='$time') AND (stop='' OR stop>'" . ($time + 60) . "') AND published='1' ORDER BY dns");
  
  		while ($objRoots->next())
  		{
  			$strDns = $objRoots->dns ?: '*';
  
  			if (isset($arrRoots[$strDns]) && $arrRoots[$strDns] == 1)
  			{
  				continue;
  			}
  
  			$arrRoots[$strDns] = $objRoots->fallback;
  		}
  
  		$arrReturn = array();
  
  		foreach ($arrRoots as $k=>$v)
  		{
  			if ($v != '')
  			{
  				continue;
  			}
  
  			if ($k == '*')
  			{
  				$arrReturn[] = '<p class="tl_error">' . $GLOBALS['TL_LANG']['ERR']['noFallbackEmpty'] . '</p>';
  			}
  			else
  			{
  				$arrReturn[] = '<p class="tl_error">' . sprintf($GLOBALS['TL_LANG']['ERR']['noFallbackDns'], $k) . '</p>';
  			}
  		}
  
  		return implode("\n", $arrReturn);
  	}
docs: Show a warning if there is no language fallback page
  
  @return string