articulate vs link up

articulate is an adjective but link up is not an adjective.

Word	Noun	Adjective	Verb	Adverb
articulate	No	Yes	Yes	No
link up	No	No	Yes	No

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

Other hypernyms of articulate include connect, join, link, unite.

articulate (adjective)	link up (adjective)
expressing yourself easily or characterized by clear expressive language
consisting of segments held together by joints

articulate (verb)	link up (verb)
speak, pronounce, or utter in a certain way	make a logical or causal connection
express or state clearly	connect, fasten, or put together two or more pieces
put into words or an expression	be or become joined or united or linked
provide with a joint
unite by forming a joint or joints