Source : Webster's Revised Unabridged Dictionary (1913)

Faltering \Fal"ter*ing\, a.
   Hesitating; trembling. ``With faltering speech.'' --Milton.
   -- n. Falter; halting; hesitation. -- {Fal"ter*ing*ly}, adv.

Source : WordNet®

falteringly
     adv : in an unsteady manner; "he walked unsteadily toward the
           exit"; "The wounded soldier was swinging unsteadily on
           his legs" [syn: {unsteadily}, {uncertainly}] [ant: {steadily}]