blather vs gabble

blather and gabble both are nouns.

Word	Noun	Adjective	Verb	Adverb
blather	Yes	No	Yes	No
gabble	Yes	No	Yes	No

As verbs, gabble is a hypernym of blather; that is, gabble is a word with a broader meaning than blather:

Other hypernyms of blather include blab, blabber, chatter, clack, gibber, maunder, palaver, piffle, prate, prattle, tattle, tittle-tattle, twaddle.

blather (noun)	gabble (noun)
foolish gibberish	rapid and indistinct speech

blather (verb)	gabble (verb)
to talk foolishly	speak (about unimportant matters) rapidly and incessantly