babble vs blether

babble and blether both are nouns.

Word	Noun	Adjective	Verb	Adverb
babble	Yes	No	Yes	No
blether	Yes	No	Yes	No

As verbs, babble and blether are synonyms defined as:

Other synonyms of babble include blather, blither, smatter.

babble (noun)	blether (noun)
gibberish resembling the sounds of a baby	idle or foolish and irrelevant talk

babble (verb)	blether (verb)
to talk foolishly	to talk foolishly
divulge confidential information or secrets
utter meaningless sounds, like a baby, or utter in an incoherent way
flow in an irregular current with a bubbling noise