- preg_match: documentation ( source)
<?php
$str = 'December 2012 Name: Jack Brown';
$ptr = "/^(?P<month>:Jan(?:uary)?|Feb(?:ruary)?|Dec(?:ember)?) (?P<year>:19[7-9]\d|2\d{3}|[0-9]{2})/";
preg_match($ptr, $str, $data);
echo $data['month'].' '.$data['year'];