I'm not sure what you are trying to do. You didn't make that very clear when you posted this.
At the moment your script:
Concatenates descFR and descEN with $id, echos out descFR, sets d## teither $REQUEST[$desc##] (although i would always use $GET or $_POST) and echos out dFR.
Are you trying to make $dFR equal to $descFR?
To be honest, i can't tell anything really from your post... you need to be clear otherwise we can't help.