The Collaborative International Dictionary of English v.0.48:

Prattle \Prat"tle\, n.
   Trifling or childish tattle; empty talk; loquacity on trivial
   subjects; prate; babble.
   [1913 Webster]

         Mere prattle, without practice.          --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Prattle \Prat"tle\, v. i. [imp. & p. p. Prattled; p. pr. & vb.
   n. Prattling.] [Freq. of prate.]
   To talk much and idly; to prate; hence, to talk lightly and
   artlessly, like a child; to utter child's talk.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Prattle \Prat"tle\, v. t.
   To utter as prattle; to babble; as, to prattle treason.
   --Addison.
   [1913 Webster]

WordNet (r) 3.0 (2006):

prattle
    n 1: idle or foolish and irrelevant talk [syn: prate,
         prattle, idle talk, blether, chin music]
    v 1: speak (about unimportant matters) rapidly and incessantly
         [syn: chatter, piffle, palaver, prate, tittle-
         tattle, twaddle, clack, maunder, prattle, blab,
         gibber, tattle, blabber, gabble]

Moby Thesaurus II by Grady Ward, 1.0:

152 Moby Thesaurus words for "prattle":
   absurdity, accents, amphigory, babble, babblement, babbling,
   balderdash, bavardage, be closeted with, bibble-babble, blab,
   blabber, blah-blah, blather, blathering, blether, blethers,
   blither, bombast, bull, bullshit, bunk, bunkum, cackle, caquet,
   caqueterie, chat, chatter, chattering, chitter-chatter, clack,
   claptrap, clatter, comment, conversation, coze, crap, discourse,
   dither, double-talk, drivel, drool, elocution, fiddle-faddle,
   fiddledeedee, flapdoodle, flummery, folderol, foolishness, fudge,
   fustian, gab, gabber, gabble, gabbling, galimatias, gam, gammon,
   garbage, gas, gibber, gibbering, gibberish, gibble-gabble, go on,
   gobbledygook, going on, gossip, guff, gush, haver, hocus-pocus,
   hogwash, hooey, hot air, humbug, idle talk, jabber, jabbering,
   jabberwocky, jargon, jaw, jawing, language, make conversation,
   maunder, maundering, mere talk, moonshine, mumbo jumbo,
   mumbo-jumbo, narrishkeit, natter, niaiserie, nonsense,
   nonsense talk, oral communication, pack of nonsense, palaver,
   palavering, parole, patter, piffle, poppycock, pour forth, prate,
   prating, prittle-prattle, ramble on, rant, rapping, rattle,
   rattle on, reel off, rigamarole, rigmarole, rodomontade, rot,
   rubbish, run on, skimble-skamble, speaking, speech, spout,
   spout off, stuff and nonsense, stultiloquence, swill, talk,
   talk away, talk nonsense, talk on, talkee-talkee, talking, tattle,
   tete-a-tete, tittle-tattle, trash, trumpery, twaddle, twattle,
   twiddle-twaddle, twitter, vapor, vaporing, visit, waffle, waffling,
   words, yak, yakkety-yak, yakking