diphthongize vs American spelling

diphthongize is not a noun while American spelling is a noun.

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

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

diphthongize (verb)	American spelling (verb)
change from a simple vowel to a diphthong