[Apfelfrucht]

Thanks a lot for your answers Tiger, i understand what do you mean
Actually, i'm trying not to use any database in order not to take a lot server ressources..

For the symbol " ' ", " _ ", and " - " are now solved and works by a coder who give me the codes like below :

function cleaner($x){
   //Replacing those weird characters with nothing.
   //This could be altered to replace them with let's say number 0.
   //Added by replacing _ with - also.
   $cleaned = preg_replace('/[^a-z0-9_.@-]/i', '', $x);
   $chars = array('@','_');
   $chars_replacement = array('at','-');
   $cleaned = str_replace($chars, $chars_replacement, $cleaned);
   return $cleaned;   
   }

So now the :
----------------
> " ' " becames " nothing ",
> " ?, ?, ?, ?, $, ?, & " becames " nothing ",
> " _ ", becames " - ".

But i wonder if is there a solution to have a script or code which transform " ?, ?, ?, ?, $, ?, & " to " e, e, a, u, $, ?, & " > I mean no accents

Someone know how please ?

Regards.