The keypress vibration is enabled on most of the Android devices by default, and you need to manually turn off or disable keyboard vibrate from the settings. On Sony Xperia devices, like Xperia Z, Xperia ZR, do as follows to disable keypress vibrate:
1. Open Settings from the app drawer
2. Under Personal settings, open Language & Input.
3. On the list of installed keyboards, tap the Settings icon next to the Xperia keyboard.
4. Tap Sound and Vibration.
5. Unmark "Vibration on keypress" to disable keyboard vibration (You have the option to increase or decrease the vibration intensity as well)