All versions of Wish I know of require the caster to speak the wish out loud. If a player did that, I'd give him the contract back and tell him to read it, or better yet, keep it and tell him to say the wish. Any significant pause in reading would be considered the end of speech. If he starts listing terms and conditions first, he's not wishing for anything, and wasted the spell. If he wishes for anything, the wish happens, and no conditions added later will be taken into account.