Google updated the Chrome web browser to let you speak to your computer instead of typing a query. The update lets you say "Ok Google" to initiate the voice command, and then you can say your question out loud instead of typing it out.
According to TechCrunch, you have to allow Chrome to access your microphone, and by enabling it once, Chrome will automatically offer the voice command feature form then on. You just go to Google.com, say "Ok Google" and then whatever it is you want to search for.
The new Chrome update only offers the "hotwording" feature in English. And it only works on Google.com. But it works pretty seamlessly for search.
This update mirrors the language Google has been trying to make happen with Google Glass, where you activate voice command by saying "Ok Glass." You can also activate Motorola's Moto X smartphone with the "Ok, Google" command.