chatter vs speak

chatter is a noun but speak is not a noun.

Word	Noun	Adjective	Verb	Adverb
chatter	Yes	No	Yes	No
speak	No	No	Yes	No

As verbs, speak is a hypernym of chatter; that is, speak is a word with a broader meaning than chatter:

Other hypernyms of chatter include mouth, talk, utter, verbalise, verbalize.

As verbs, speak is a hypernym of chatter; that is, speak is a word with a broader meaning than chatter:

Other hypernyms of chatter include mouth, talk, utter, verbalise, verbalize.

chatter (noun)	speak (noun)
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)	speak (verb)
speak (about unimportant matters) rapidly and incessantly	express in speech
talk socially without exchanging too much information	exchange thoughts; talk with
make noise as if chattering away	use language
cut unevenly with a chattering tool	give a speech to
click repeatedly or uncontrollably	make a characteristic or natural sound