articulate vs couch

articulate is not a noun while couch is a noun.

Word	Noun	Adjective	Verb	Adverb
articulate	No	Yes	Yes	No
couch	Yes	No	Yes	No

As verbs, couch is a hyponym of articulate; that is, couch is a word with a more specific, narrower meaning than articulate:

Other hyponyms of articulate include ask, lexicalise, lexicalize, dogmatise, dogmatize, formularise, formularize, cast, frame, put, redact.

articulate (noun)	couch (noun)
	an upholstered seat for more than one person
	a narrow bed on which a patient lies during psychiatric or psychoanalytic treatment
	a flat coat of paint or varnish used by artists as a primer

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

articulate (verb)	couch (verb)
speak, pronounce, or utter in a certain way	formulate in a particular style or language
express or state clearly
put into words or an expression
provide with a joint
unite by forming a joint or joints