The Collaborative International Dictionary of English v.0.48:

Cackle \Cac"kle\, v. i. [imp. & p. p. Cackled (-k'ld); p. pr.
   & vb. n. Cackling.] [OE. cakelen; cf. LG. kakeln, D.
   kakelen, G. gackeln, gackern; all of imitative origin. Cf.
   Gagle, Cake to cackle.]
   1. To make a sharp, broken noise or cry, as a hen or goose
      does.
      [1913 Webster]

            When every goose is cackling.         --Shak.
      [1913 Webster]

   2. To laugh with a broken noise, like the cackling of a hen
      or a goose; to giggle. --Arbuthnot.
      [1913 Webster]

   3. To talk in a silly manner; to prattle. --Johnson.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Cackle \Cac"kle\, n.
   1. The sharp broken noise made by a goose or by a hen that
      has laid an egg.
      [1913 Webster]

            By her cackle saved the state.        --Dryden.
      [1913 Webster]

   2. Idle talk; silly prattle.
      [1913 Webster]

            There is a buzz and cackle all around regarding the
            sermon.                               --Thackeray.
      [1913 Webster]

WordNet (r) 3.0 (2006):

cackle
    n 1: the sound made by a hen after laying an egg
    2: noisy talk [syn: yak, yack, yakety-yak, chatter,
       cackle]
    3: a loud laugh suggestive of a hen's cackle
    v 1: talk or utter in a cackling manner; "The women cackled when
         they saw the movie star step out of the limousine"
    2: squawk shrilly and loudly, characteristic of hens
    3: emit a loud, unpleasant kind of laughing

Moby Thesaurus II by Grady Ward, 1.0:

40 Moby Thesaurus words for "cackle":
   call, carol, caw, chatter, cheep, chirk, chirp, chirr, chirrup,
   chitter, chuck, clack, cluck, coo, croak, cronk, crow, cuckoo,
   drum, gabble, gaggle, gobble, guggle, honk, hoo, hoot, peep, pip,
   pipe, quack, roll, scold, sing, squawk, trill, tweet, twit,
   twitter, warble, whistle



Moby Thesaurus II by Grady Ward, 1.0:

198 Moby Thesaurus words for "cackle":
   Homeric laughter, babble, babblement, bark, bavardage, bawl,
   be in stitches, belch, bellow, belly laugh, bibble-babble, blab,
   blabber, blah-blah, blare, blat, blather, blether, blethers,
   blubber, boff, boffola, boom, bray, break up, breathe, burr,
   burst into laughter, burst of laughter, burst out,
   burst out laughing, burst with laughter, bust a gut, buzz,
   cachinnate, cachinnation, call, caquet, caqueterie, carol, caw,
   chant, chat, chatter, cheep, chirk, chirp, chirr, chirrup, chitter,
   chitter-chatter, chortle, chuck, chuckle, clack, clang, clangor,
   clank, clash, clatter, cluck, cock-a-doodle-doo, convulsion, coo,
   craunch, croak, cronk, crow, crump, crunch, cuckoo, drawl, drum,
   exclaim, fit of laughter, flute, gab, gabble, gaggle,
   gales of laughter, gas, gasp, gibber, gibble-gabble, giggle,
   go into convulsions, gobble, gossip, grind, groan, growl, grumble,
   grunt, guff, guffaw, guggle, ha-ha, hearty laugh, hee-haw, hee-hee,
   hilarity, hiss, ho-ho, honk, hoo, hoot, horselaugh, hot air,
   idle talk, jabber, jangle, jar, keen, laugh, laugh it up,
   laugh outright, laughing, laughter, lilt, mere talk, mumble,
   murmur, mutter, natter, nearly die laughing, nonsense talk,
   outburst of laughter, palaver, pant, peal of laughter, peep, pip,
   pipe, prate, prating, prattle, prittle-prattle, quack, rasp,
   risibility, roar, roar of laughter, roar with laughter, roll,
   rumble, scold, scranch, scrape, scratch, scream, screech, scrunch,
   shake like jelly, shake with laughter, shout, shout of laughter,
   shriek, sibilate, sigh, sing, snap, snarl, snicker, snigger, snore,
   snort, sob, split, split with laughter, squall, squawk, squeal,
   talkee-talkee, tee-hee, thunder, titter, tittle-tattle, trill,
   trumpet, twaddle, twang, twattle, tweet, twit, twitter, wail,
   warble, whine, whisper, whistle, yak, yakkety-yak, yap, yawp, yell,
   yelp, yuck, yuk-yuk