Structuring the Taman Shud code cracking process

1) Assumption 1: The code is jibberish. This is what we will do.......

      2) Assumption 2:     The code is in English, but the letters have been substituted.
                                       This is what we will do.........
      3) Assumption 3:     The code is in English and the letters are as they are supposed to be.
                                        This is what we will do.......
      4) Assumption 4:     The code is in a foreign language.  This is what we will do.......
                                        (I think you need to restrict this case to foreign + no character
                                         substitution. You do not have time to attack the case of foreign
                                         with substitution.....you have to say that is beyond the scope of the pro