assibilate vs assibilation

assibilate is not a noun while assibilation is a noun.

Word	Noun	Adjective	Verb	Adverb
assibilate	No	No	Yes	No
assibilation	Yes	No	No	No

assibilate (noun)	assibilation (noun)
	pronunciation with a sibilant (hissing or whistling) sound
	the development of a consonant phoneme into a sibilant

assibilate (verb)	assibilation (verb)
change into a sibilant
insert a sibilant sound before or after (another sound)