linguistics vs segmental

linguistics is a noun but segmental is not a noun.

Word	Noun	Adjective	Verb	Adverb
linguistics	Yes	No	No	No
segmental	No	Yes	No	No

linguistics (noun)	segmental (noun)
the scientific study of language
the humanistic study of language and literature

linguistics (adjective)	segmental (adjective)
	having the body divided into successive metameres or segments, as in earthworms or lobsters
	divided or organized into speech segments or isolable speech sounds