prattle

from The American Heritage® Dictionary of the English Language, 5th Edition.

• intransitive verb To talk or chatter idly or meaninglessly; babble or prate.
• intransitive verb To utter or express by chattering foolishly or babbling.
• noun Idle or meaningless chatter; babble.

from The Century Dictionary.

• To talk artlessly and childishly; talk freely and idly, like a child; chatter; be loquacious; prate.
• To force or effect by talking; bring or lead by prattling.
• To utter in a babbling or childish manner.
• noun Artless or childish talk; hence, puerile loquacity; twaddle.
• noun Synonyms Prattle, Prating, Chat, Chatter, Babble, Tattle, Gossip, Gabble, Palaver, Twaddle, Gibberish, Jargon, Balderdash, Rigmarole. Prattle is generally harmless, if not pleasant, as the prattle of a child, or of a simple-minded person; prating now generally suggests the idea of boasting or talking above one's knowledge; chat is easy conversation upon light and agreeable subjects, as social chat beside an open fire; chatter is incessant or abundant talk, seeming rather foolish and sounding pretty much alike; babble or babbling is talk that is foolish to inaneness, as that of the drunkard (Prov. xxiii. 29); tattle is talk upon subjects that are petty, and especially such as breed scandal; gossip is the small talk of the neighborhood, especially upon personal matters, perhaps dealing with scandal; gabble is a contemptuous word, putting the talk upon the level of the sounds made by geese; palaver implies that the talk is either longer than is necessary, or wordy, or meant to deceive by flattery and plausibility; twaddle is mere silliness in talk; gibberish is mere sounds strung together without sense; jargon is talk that is unintelligible by the mingling of sounds or by the lack of meaning; balderdash is noisy nonsense; rigmarole is talk that has the form of sense, but is really incoherent, confused, or nonsensical.

from the GNU version of the Collaborative International Dictionary of English.

• intransitive verb To talk much and idly; to prate; hence, to talk lightly and artlessly, like a child; to utter child's talk.
• transitive verb To utter as prattle; to babble.
• noun Trifling or childish tattle; empty talk; loquacity on trivial subjects; prate; babble.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb to talk incessantly and in a childish manner; to babble.
• noun Silly, childish, talk; babble.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb speak (about unimportant matters) rapidly and incessantly
• noun idle or foolish and irrelevant talk