The Collaborative International Dictionary of English v.0.48:

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.
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            The jaw makes answer, as the magpie chatters.
                                                  --Wordsworth.
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   2. To talk idly, carelessly, or with undue rapidity; to
      jabber; to prate.
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            To tame a shrew, and charm her chattering tongue.
                                                  --Shak.
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   3. To make a noise by rapid collisions.
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            With chattering teeth, and bristling hair upright.
                                                  --Dryden.
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