Definitions of chatter:

• noun:   the high-pitched continuing noise made by animals (birds or monkeys)
• noun:   the rapid series of noises made by the parts of a machine
• noun:   noisy talk
• verb:   click repeatedly or uncontrollably

  Example: "Chattering teeth"

• verb:   speak (about unimportant matters) rapidly and incessantly
• verb:   make noise as if chattering away

  Example: "The magpies were chattering in the trees"

• verb:   cut unevenly with a chattering tool
• verb:   talk socially without exchanging too much information