Definitions of twitter on the Web:

chitter: make high-pitched sounds, as of birds
chirrup: a series of chirps

wordnet.princeton.edu/perl/webwn

Twitter is a free social networking and micro-blogging service that allows its users to send and read other users’ updates (otherwise known as …

en.wikipedia.org/wiki/Twitter

a succession of chirps as uttered by birds; to utter a succession of bird’s chirps; (of a person) to talk in an excited or nervous manner

en.wiktionary.org/wiki/twitter

twittery – that twitters

en.wiktionary.org/wiki/twittery

twittering – twitters fundamental question is “what are you doing?” This is can be in its most simplistic for a one or two word …