American spelling vs overspecialize

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

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

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

American spelling (verb)	overspecialize (verb)
	become overly specialized