The intonation, I think, is from North America where they use it to pose a
question when words are missed out that are crucial to the questioning
sentence.

I think it was Stephen Fry who once put AQI (HRT in America) into Room 101.
It stands for Australian Questioning Intonation though I believe, as you
say, it originated in the States.

More he

http://en.wikipedia.org/wiki/High_rising_terminal
________________
Nick G
Otter Valley, Devon
83 m amsl
http://www.ottervalley.co.uk