The Collaborative International Dictionary of English v.0.48:

Garrulous \Gar"ru*lous\, a. [L. garrulus, fr. garrire to
   chatter, talk; cf. Gr. ? voice, ? to speak, sing. Cf.
   Call.]
   1. Talking much, especially about commonplace or trivial
      things; talkative; loquacious.
      [1913 Webster]

            The most garrulous people on earth.   --De Quincey.
      [1913 Webster]

   2. (Zool.) Having a loud, harsh note; noisy; -- said of
      birds; as, the garrulous roller.

   Syn: Garrulous, Talkative, Loquacious.

   Usage: A garrulous person indulges in long, prosy talk, with
          frequent repetitions and lengthened details; talkative
          implies simply a great desire to talk; and loquacious
          a great flow of words at command. A child is
          talkative; a lively woman is loquacious; an old man in
          his dotage is garrulous. -- Gar"ru*lous*ly, adv. --
          Gar"ru*lous*ness, n.
          [1913 Webster]

WordNet (r) 3.0 (2006):

garrulousness
    n 1: the quality of being wordy and talkative [syn: garrulity,
         garrulousness, loquaciousness, loquacity,
         talkativeness]