The Google voice search feature was announced at I/O just recently, and it’s already been released for the least version of Chrome, which is 27.
Basically, when you access the Google Voice search feature, you will actually get a verbal response from the top of the web page screen. The search feature also enables relative search, which means that if you ask about a particular person or object, you can continue asking questions related to that subject without having to repeat the same information or question, and Google would still know who or what you’re talking about.