90% of Australian communication is either that or thinly veiled barbs asserting your social position.

Some people reckon HRT (or AQI as below) is exactly that

But far from indicating insecurity, some studies suggest that the AQI is often used by powerful people when speaking to their subordinates (thereby explaining why Australians use it when talking to Britons). The theory is that it's much more acceptable for a boss to ask an employee whether they understand something than vice versa. Linguists also believe the high-rising can serve other purposes. A rising intonation at the end of a statement (giving directions, for example) implicitly asks the listener to confirm that they understand what they've been told. Alternatively, it can be used to stop an anticipated interruption.