
- Project Butter : improving UI responsiveness.
 - Keyboard and voice input : better and more accurate predictive input and extended dictionary. Voice Typing in now available offline.
 - Camera : new UI and gestures.
 - Notifications : Music, Pulse and Gmail to be expanded to give you more details without having to open the app.
 - Google Search : Natural language commands are now supported.
 
Jelly Bean will be available mid-July with a developer SDK preview available right now on the Android Developers website.
For more in depth detail, hit the source below.
[SOURCE]