PHPstrtr()

strtr()
strtr(string,from,to)
strtr(string,array)
string1
from
to
array

<?php
echo strtr("Hilla Warld","ia","eo");
?>

Hello World

<?php
$arr = array("Hello" => "Hi", "world" => "earth");
echo strtr("Hello world",$arr);
?>

Hi earth