That boy is a chatterbox.

Quit chattering.

She is, in brief, a chatterbox.

Her continuous chatter vexes me.

Sven was so verbose that his friends resorted to calling him a chatterbox.

She's a chatterbox.

Tom was so cold his teeth were chattering.

Don't chatter! I have to study.

It was so cold that my teeth were chattering.

So engrossed was he with his occupation that he appeared to have forgotten our presence, for he chattered away to himself under his breath the whole time, keeping up a running fire of exclamations, groans, whistles, and little cries suggestive of encouragement and of hope.