The Collaborative International Dictionary of English v.0.48:

Haltingly \Halt"ing*ly\ (h[add]lt"[i^]ng*l[y^]), adv.
   In a halting or limping manner.
   [1913 Webster]

WordNet (r) 3.0 (2006):

haltingly
    adv 1: in a halting manner; "he spoke haltingly"

Moby Thesaurus II by Grady Ward, 1.0:

73 Moby Thesaurus words for "haltingly":
   at irregular intervals, at random, brokenly, by catches, by fits,
   by jerks, by snatches, capriciously, cautiously, circumspectly,
   crawlingly, creepingly, deliberately, desultorily, dilatorily,
   disconnectedly, discontinuously, easily, eccentrically,
   erratically, falteringly, fitfully, gently, idly, in low gear,
   in march time, in slow motion, in slow tempo, in snatches,
   in spots, inconstantly, indolently, intermittently, irregularly,
   jerkily, languidly, languorously, leisurely, limpingly,
   lingeringly, loiteringly, lurchingly, moderately, nonuniformly,
   off and on, patchily, pokily, pokingly, relaxedly, reluctantly,
   roughly, slow, slowly, sluggishly, spasmodically, sporadically,
   spottily, tarryingly, tentatively, uncertainly, under easy sail,
   unevenly, unhurriedly, unmethodically, unpredictably,
   unrhythmically, unsteadily, unsystematically, variably,
   whimsically, with agonizing slowness, with deliberation,
   wobblingly