Make the text in the slidebox translatable

By changing slidebox.tpl.php to something like

<div id="slidebox">
  <a class="close"></a>
  <p><?php echo t('next post') ?></p>
  <h2><?php echo $title; ?></h2>
  <?php echo l(t ('Read More &raquo;'), "node/{$nid}", array('html' => TRUE, 'attributes' => array('class' => array('more')))); ?>
</div>
<div id="slidebox_manual">
  <a class="open"></a>
</div>
<div id="slidebox_cookie">
  <a class="set"><?php echo t('Do not show recommendations again this session.') ?></a>
</div>

I'm not a coder, in the last link for not showing again this session I cheated by removing the ' in Don't and write " Do not" . Else it will brake the code. I'm sure there is a better way of doing it.