It turns out that “chat” is the “onomatopoeic abbreviation of chatter”, and “chatter” is itself onomatopoeic. I find this connection between Gollum and the Master of Laketown eerily satisfying.
- 05.022 and chats with it a bitsy,
- 14.030 but the Master ground his chattering teeth.
“chat, v.1.” OED Online. Oxford University Press, March 2015. Web. 22 May 2015.