Source : Webster's Revised Unabridged Dictionary (1913)

Chatter \Chat"ter\, v. i. [imp. & p. p. {Chattered}; p. pr. &
   vb. n. {Chattering}.] [Of imitative origin. Cf. {Chat}, v. i.
   {Chitter}.]
   1. To utter sounds which somewhat resemble language, but are
      inarticulate and indistinct.

            The jaw makes answer, as the magpie chatters.
                                                  --Wordsworth.

   2. To talk idly, carelessly, or with undue rapidity; to
      jabber; to prate.

            To tame a shrew, and charm her chattering tongue.
                                                  --Shak.

   3. To make a noise by rapid collisions.

            With chattering teeth, and bristling hair upright.
                                                  --Dryden.

Chattering \Chat"ter*ing\, n.
   The act or habit of talking idly or rapidly, or of making
   inarticulate sounds; the sounds so made; noise made by the
   collision of the teeth; chatter.

Source : WordNet®

chattering
     adj : engaged in making a rapid repetitive noise resembling
           speech; "the chattering sparrows"
     n 1: the rapid series of noises made by the parts of a machine
          [syn: {chatter}]
     2: the high-pitched continuing noise made by animals (birds or
        monkeys) [syn: {chatter}]