funciton returs 0

[StrangerInBeijing]

first off....php noob...enough said
I created this function to build the items to go in a list:

  function get_lang_menu()
  {
    $lang = get_text("en", "ja", "zh", "de");
    $temp = '';
    if ($lang=="en")  {
      $temp += '<li>English</li>';
    }  else  {
      $temp += '<li><a href="../index.php?lang=en">English</a></li>';
    }
    if ($lang=="ja")  {
      $temp += '<li>Japanese</li>';
    }  else  {
      $temp += '<li><a href="../index.php?lang=ja">Japanese</a></li>';
    }
    if ($lang=="zh")  {
      $temp += '<li>Chinese</li>';
    }  else  {
      $temp += '<li><a href="../index.php?lang=zh">Chinese</a></li>';
    }
    if ($lang=="de")  {
      $temp += '<li>German</li>';
    }  else  {
      $temp += '<li><a href="../index.php?lang=zh">German</a></li>';
    }
    return $temp;
    //return '<li><a href="../index.php?lang=en">English</a></li><li><a href="../index.php?lang=ja">Japanese</a></li><li><a href="../index.php?lang=zh">Chinese</a></li><li><a href="../index.php?lang=de">German</a></li>';
  }

The "get_text" call does return a value. I checked. But when I call this function like this:

<?php echo(get_lang_menu()) ?>

, a 0 get printed out.
If i switch out the last two return lines (comment out one) it works fine with the second hard coded string.
So I assume my if statement is not what it should be.......right?