Google Translate has been available for a long time now and can translate text or webpages with a single click. Well Google is working on a way to do that with your voice quite similar to the way it worked in Star Trek. Google is calling it Conversation Mode on Google Translate. However Google is no where near to releasing it to the public, Google states that it is in early beta.
When you enter Conversation Mode, each person will select their native language. Then each person will speak to the device and when finished the device will translate what was spoken and speak it to the other person in their native language and vice versa. This was announced back in February by TheTimes and was recently discussed and demonstrated at TechCrunch’s Disrupt which you can see here. The demonstration is quite promising with few bugs which I would assume would be worked out by Google. But with this technology we could be moving closer to the nirvana that Star Trek had.