Google I/O starts today, the event usually runs for two days, but on the first day we see the keynote where Google usually makes some very important announcements.
Google I/O is mainly aimed at developers so there will be more technical language. We usually see what Google has planned for the future.
There are many things to expect from this years event, including a new version of Android, more info on Android Wear, Android for the car and home, maybe a new Nexus phone or tablet and some updates on Google Glass.
The livestream starts at 5PM London time (9AM PT, 12PM ET).