Much like the Xbox Kinect, your PlayStation 4 can listen to you and do what you say. You just need an earphone/headphone with a mic and then you can order your PS4 with various voice commands!
To use voice commands on a PS4, follow these steps:
Go to "Settings". Select "System" option.
Select "Voice Operation Settings".
Check the "Operate PS4 with Voice" option. You select "View Guide" option for more info.
Now you are ready to command your PlayStation. Make sure you have plugged an earphone/headphone with a mic on your DualShock controller. Just say "PlayStation" followed by your commands like open Netflix, take a screenshot, etc.