$re = '~\[[^][]*pause="(?P<type>[^"]+)"~m';
$str = 'Hi[pause="x-weak"]Parth[pause="weak"]How[pause="medium"]are[pause="strong"]You[pause="x-strong"]tell me';
preg_match_all($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