The consciousness in [Australia and New Zealand] of the elevation of a substandard dialect into a national tongue has been responsible for a mixture of attitudes to citizens of the mother country - inferiority, defiance, contempt. A blending of the first two may be responsible for the upward intonation pattern of answers, more appropriate to questions….slang is of its nature defiant. It is also demotic….But the ruling class of Australia is itself demotic.
Anthony Burgess