falter vs speak

falter is a noun but speak is not a noun.

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

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

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

falter (noun)	speak (noun)
the act of pausing uncertainly

falter (verb)	speak (verb)
speak haltingly	express in speech
walk unsteadily, tripping repeatedly	exchange thoughts; talk with
move hesitatingly, as if about to give way	use language
be unsure or weak	give a speech to
	make a characteristic or natural sound