babble vs babble out

babble is a noun but babble out is not a noun.

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

As verbs, babble and babble out are synonyms defined as:

Other synonyms of babble include blab, blab out, let the cat out of the bag, peach, sing, spill the beans, talk, tattle.

babble (noun)	babble out (noun)
gibberish resembling the sounds of a baby

babble (verb)	babble out (verb)
to talk foolishly	divulge confidential information or secrets
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