Check out the format strings available with the date function.
You can't use it directly to translate 2 to Feb, but you could probably write your own function that pieces it together into a timestamp with mktime
and then use that timestamp to format the date with a short textual representation of the month.
Something like so (untested):
$timestamp = mktime(0, 0, 0, $n, 1, 2005);
return date("M", $timestamp);