$re = '~<td[^>]*>\s*(?:.(?!</td>))+\s*<\?php audioButton\("[^"]*/(.+?)","(.*?)"\);.*?\?>.*?</td>~';
$str = '<td class="danish">kat
<?php audioButton("../../audio/words/dog","dog");?></td>
<td class="danish">kat
<?php audioButton("../../audio/words/dog","dog");?></td>
<td class="danish">kat</td>
<td><?php audioButton("../../audio/words/dog","dog");?></td>
<td class="danish">kat
<?php audioButton("../../audio/words/dog","dog");?></td>';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php