speak up vs verbalize

speak up and verbalize both are verbs.

Word	Noun	Adjective	Verb	Adverb
speak up	No	No	Yes	No
verbalize	No	No	Yes	No

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

Other hypernyms of speak up include mouth, speak, talk, utter, verbalise.

speak up (verb)	verbalize (verb)
express one's opinion openly and without fear or hesitation	convert into a verb
speak louder; raise one's voice	express in speech
	be verbose
	articulate; either verbally or with a cry, shout, or noise