BGR`s report confirms these two features saying that version iOS 5.1 has a fixed slider camera button located next to the unlock button which you quickly slide instead of tapping the Home button twice to launch your camera app.
The report also confirms Siri`s support for the Japanese language as showcased in Settings. That agrees also with a previous report suggesting that Siri will indeed support three more languages by next month.
iOS 5.1 is expected to roll out in the coming few weeks. Stay tuned!!