How to make unique random sentence

hei,

I need a random words in my sentences like this, you have 4 words = 'Crazy','Lidya','Super','Hello' then i need to make the result like this example: LidyaHello or HelloSuper

<?php
$role = array("Crazy","Lidya","Super","Hello");
$tamvan = $role[array_rand($role)];
echo $tamvan,$tamvan;
?>

but the result that i get is the same word example : LidyaLidya or HelloHello