"Ich bin ein Berliner." That was a direct quote from President John F. Kennedy when he announced it to West Berlin in 1963. The German people roared with laughter as Kennedy thought he had successfully charmed them. While he did achieve that goal, he didn't however get his message across, considering that he just proclaimed to the people of Germany that he was a jelly doughnut!
That event clearly demonstrates that language is both a medium and a process. Consider the following example: suppose you and I are watching a foreign film with no subtitles. How do we make out the language? Where do we begin? Simply repeating the words will not do much good because all we'll be doing is repeating the sounds, but not the language, we would be responding in gibberish. So, what are we to do? Enter the universal translator. This nifty little device was created by Gene Roddenberry and quickly became a solution and plot device for language barriers.
But now, let's look at how it works. To start off, it's a computer dictionary. But it's much more than that, it also carries the speakers mood, attitude, the content and context of the speech, as well as tone, and mood. Hence, it's accessing the rest of the mind/brain, not just connections and thoughts associated with language. If that is the case, this device is commiting a major breach of ethics. Given this scenerio, people such as telepaths and empaths like Counselor Troi would be out of a job.
But what's really amazing about the universal translator is that unlike the other technologies in Trek such as: replicators, transporters, and holodecks, the unversal translator has never ever failed or malfunctioned. It would have been far more plausible if the writers introduced initial lags and delays in the device when dealing with new species, then less hesitation and fewer errors over time as the translator sorted out the patterns of the new language, and yet this strangely never happens.
Even if that weren't the case, there would still be major ostacles when dealing with different lifeforms. The Vulcans and Betazoids have paranormal abilities, the Ferengi have four cortical lobes, and the Trills must have special neural connections for symbionts. There is no guarantee that their languages with coincide. As a matter of fact, there is an excellent Next Generation episode entitled, "Darmok" which highlights how rocky communication can really become when words are shared, but not concepts. The Tamarians in "Darmok" are a humanoid society, but they think exclusively in extended metaphors, that is, the sentences that come out are perfectly recognizable, but the context is missing.
Well, that rules out the Star Trek universal translator type, but could we build something similar? Of course. There is a universal translator called, ViA and it works by processing and translating existing known languages. Let's say an american businessman has to send a fax to a customer in Japan, all he does is faxes it in english and it comes out in japanese in Japan. This will also be useful in emergency situations as well. For more info: click on the following link:
Note: this only works for existing languages, but to translate an unknown language will take time and patience. Still, it's pretty close to the one in Star Trek, but without all the mind-reading stuff. Pretty cool, huh?