open up vs speak

open up and speak both are verbs.

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

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

Other hypernyms of open up include mouth, talk, utter, verbalise, verbalize.

open up (verb)	speak (verb)
make available	express in speech
become available	exchange thoughts; talk with
talk freely and without inhibition	use language
cause to open or to become open	give a speech to
become open	make a characteristic or natural sound
open up an area or prepare a way
start to operate or function or cause to start operating or functioning