British spelling vs extemporisation

British spelling and extemporisation both are nouns.

Word	Noun	Adjective	Verb	Adverb
British spelling	Yes	No	No	No
extemporisation	Yes	No	No	No

British spelling (noun)	extemporisation (noun)
English orthography used in the UK, Ireland and most of the Commonwealth (characterized by 'analyse', 'centre' and 'useable')	a performance given extempore without planning or preparation