chatter vs yakety-yak

chatter and yakety-yak both are nouns.

Word	Noun	Adjective	Verb	Adverb
chatter	Yes	No	Yes	No
yakety-yak	Yes	No	No	No

As nouns, chatter and yakety-yak are synonyms defined as:

Other synonyms of chatter include cackle, yack, yak.

chatter (noun)	yakety-yak (noun)
noisy talk	noisy talk
the high-pitched continuing noise made by animals (birds or monkeys)
the rapid series of noises made by the parts of a machine

chatter (verb)	yakety-yak (verb)
speak (about unimportant matters) rapidly and incessantly
talk socially without exchanging too much information
make noise as if chattering away
cut unevenly with a chattering tool
click repeatedly or uncontrollably