Disable translation of watchdog messages
I made it like this:

function MYADMINTHEME_dblog_message($variables) {
  $output = '';
  $event = $variables['event'];
  // Check for required properties.
  if (isset($event-&gt;message) &amp;&amp; isset($event-&gt;variables)) {
    // Messages without variables or user specified text.
    if ($event-&gt;variables === 'N;') {
      $output = $event-&gt;message;
    }
    // Message to translate with injected variables.
    else {
      $output = format_string($event-&gt;message, unserialize($event-&gt;variables));
    }
    if ($variables['link'] &amp;&amp; isset($event-&gt;wid)) {
      // Truncate message to 56 chars.
      $output = truncate_utf8(filter_xss($output, array()), 56, TRUE, TRUE);
      $output = l($output, 'admin/reports/event/' . $event-&gt;wid, array('html' =&gt; TRUE));
    }
  }
  return $output;
}