Sort the Spelling Words!

ee,ea,ey,e_e,y

ey
    ea
      ee
        e_e
          y

            ai,ay,a_e

            ai
              ay
                a_e

                  ie,igh,y,i_e

                  igh
                    ie
                      y
                        i_e

                          oa,ow,o_e

                          ow
                            oa
                              oe

                                ue,u_e,ew

                                ue
                                  ew
                                    u_e