"I'm thinking of things that begin with the letter . ." J

Jumping
  Jewelry
     Jalopy
        Jennifer
             Jello
               Jalal
                  Jester
                   Jurgens
                    Jasper
                   Jacks
                 Joints
               Jet
             Jill
           Jolly
          Jurisdiction
           Jessa
            Jackson
             Janet
               Jar
                Jam
                  Joyous
                     Jeffrey
                        Jousting
                             Jammies
                               Journalist
                            Jamestown        
                          Justification
                       Jurisprudence       
                     Jointly
                  Jeopardy
               Jeep
            Jared
          Jaded
       Joyce
    Jail
  Juxtapose
Jesuit
Jesus
   Jean
     Jeans
        Jabber
           Jabberwocky