*** Guide-to-Links ***
 HM HM is used to link to hesitation markers (planners, fillers): 
                  +----Pp----+
              +-Ss+>HM>+     +--Js-+
              |   |    |     |     |
     I think it  's   uhh  from  Mars

                       +---Js---+
              +-Ss+-Pp-+>HM>+   |
              |   |    |    |   |
     I think it  's  from  uhh Mars
Grammar Documentation Page.