Those using iPhone 4S cant ignore Apple’s latest feature of Siri, making use of your iPhone simpler and better. Commands given in your language being acted upon at once, seems to be a very easy and hassle free approach.
I experienced it so often that I thought my iPhone has some fault but when I searched I came to know a lot of others are going through the same agony. Finally, I found the solution which is strange but true.
Most probably, we are holding it wrong in the first place. Lift the phone exactly the way you use it normally and then twist it while moving to the side of your head. There you go; this feature of Siri is activated. It is made that way may be to avoid any accidental activation.