$ltr = array(
"a" => 1,
"b" => 2,
"c" => 3,
"d" => 4,
"e" => 5,
"f" => 6,
"g" => 7,
"h" => 8,
"i" => 9,
"j" => 10,
"k" => 11,
"l" => 12,
"m" => 13,
"n" => 14,
"o" => 15,
"p" => 16,
"q" => 17,
"r" => 18,
"s" => 19,
"t" => 20,
"u" => 21,
"v" => 22,
"w" => 23,
"x" => 24,
"y" => 25,
"z" => 26);
$string = "goatey";
$string = strtolower($string);
$new_string = "";
for($i = 0; $i < strlen($string); $i++) {
$letter = substr($string, $i, 1);
$new_string .= $ltr[$letter];
if($i < (strlen($string) - 1)) {
$new_string .= ", ";
}
}
echo $new_string;