S Voice is a Siri alternative to Samsung Galaxy S 3. I have used this feature in Galaxy S 3 and believe me, it’s amazing. It can easily understand Indian accent and give response very quickly.
You can give instructions to your phone by pressing home button twice quickly. If you press the home button once, the response time is low because your phone waits for the second press. To get rid of slow behavior of home button you can disable S-Voice in Settings. Just go to Settings and then S Voice settings. Uncheck the box next to “Launch S Voice”. All done.