Wiktionary
quaveringly
adv. In a quavering manner; tremulously.
WordNet
quaveringly
adv. in an unsteady quavering manner; "the man began quaveringly to question the soldier"
Usage examples of "quaveringly".
She must have heard them enter, for her voice addressed them quaveringly from behind the curtains.
That unfortunate gentleman licked his lips and said quaveringly: ‘I shall not fight you, sir.