diphthongise vs Australian spelling

diphthongise is not a noun while Australian spelling is a noun.

Word	Noun	Adjective	Verb	Adverb
diphthongise	No	No	Yes	No
Australian spelling	Yes	No	No	No

diphthongise (noun)	Australian spelling (noun)
	English orthography used in Australia (characterized by 'analyse', 'centre', 'usable')

diphthongise (verb)	Australian spelling (verb)
change from a simple vowel to a diphthong