Output random words

I have to write a program that will output random words(with random letters) and that will not have 3 vocals or consonants near, so i wrote:

$array=array();

$n=10;

for ($i=0;$i<$n;$i++){
$l=rand(4,10);                                   // $l=word length
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    for ($j=0;$j<$l;$j++){

        $cas=rand(65,90);                        //$cas=random letters
        $array[$j]=$cas; 


        if($j>1){   
if (($array[$j-1]==65 || $array[$j-1]==69 || $array[$j-1]==73 || $array[$j-1]==79 || $array[$j-1]==85) ^ ($array[$j-2]==65|| $array[$j-2]==69 || $array[$j-2]==73 || $array[$j-2]==79 || $array[$j-2]==85)){                //will do XOR '^'


        $cas=rand(65,90);                                                          
        $array[$j]=$cas;                          

                     }
        }

           $m=chr($array[$j]);   
             echo $m;
    }
}

?>

don't know why but it seems that IF doesn't work, 'cause when I output it'll print also words with 3 or more consonants or vocal. Can anybody help me? thanks :D and sorry for bad english :P