American spelling vs sizable

American spelling is a noun but sizable is not a noun.

Word	Noun	Adjective	Verb	Adverb
American spelling	Yes	No	No	No
sizable	No	Yes	No	No

American spelling (noun)	sizable (noun)
English orthography used in the United States (characterized by 'analyze', 'center', 'usable')

American spelling (adjective)	sizable (adjective)
	large in amount or extent or degree
	fairly large in size