How does the Universal Translator work?

Question

In Star Trek Voyager, The 37's, its revealed that the Universal Translator somehow turns speech into the recipient's (the person hearing) language for each individual person, regardless of how many there are in the vicinity.

The Japanese guy even says:

you are speaking Japanese

From this it is apparent that they don't even hear Janeway's actual words, but only the translated version, as if she'd spoken that language naturally.

Reason I ask is that if the U.T. simply gave an audio translation, then every speech would be a jumble of languages.

Also, the 37's wouldn't have any implanted devices to help with this. By all appearances, it seems they hear the translation as an audible thing.

How can this be possible? It the U.T. somehow projecting the translation into the recipient's mind, and nullifying the original physical sound?

Canon answers (or from the technical manual) preferred, but also any real-world research could be interesting.

Answer 1

Yes. The Universal Translator works on brain waves... for reading. It scans the brain for basic universal patterns, cross references them to translation matrixes. But No, it does not project them, and is supposed to produce audio. This is more obvious with later series, Enterprise, and Nu-Trek. From Memory Alpha:

We establish a "telecommunicator" device early in the series, little more complicated than a small transistor radio carried in a pocket. A simple "two-way scrambler", it appears to be converting all spoken language into English. (Roddenberry 11)

Furthermore:

During the writing of "The Corbomite Maneuver" (the first regular installment of Star Trek, following the pilot episodes "The Cage" and "Where No Man Has Gone Before"), the universal translator underwent some further development. Jerry Sohl, the writer of "The Corbomite Maneuver", later explained, "We were originally going to have [each crew member] carry a language translator, which would fit on the wrist like a beeper, and no matter what area of the universe they were in, the thoughts that the people were thinking would automatically be translated into English as they spoke. We got rid of that idea, and assumed that everybody did speak English." (The Star Trek Interview Book, pp. 127-128)

Obviously it is not 100% screen accurate, because this is a cinematic convention. It is used to explain away the English we hear. In Nu-Trek, the translator has an audio delay, and the listeners hear both the original and translated versions, like a real life translator.

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Keep in mind its easy enough to explain away with science and technology. Directional audio can be produce with speaker arrays. You can cancel out audio by producing audio 180 degrees out of phase. Assuming a few hundred years of technological advancement, noise cancelation could be real time.

The translator can "detect" when someone doesn't want to be translated.

Lastly, the problem of lip syncing and visual translations. It is never addressed directly in or out of universe. Since Star Trek is Science Fiction, and entertainment, the realism is ignored to make it easier on the audience, and hand waved as "technology got better".

Keep in mind, Star Trek is a universe where things like subspace allow real time communication with no lag over interstellar distances. We can't even talk to the moon without a delay (2.6 seconds round trip). Hell, we still have lag with Earth bound communication.

Answer 2

I always felt that the Star Trek UT worked directly with the brainwaves. It was similar to Farscape’s translator microbes, it make you FEEL that the other person was speaking in your language. This is actually shown in an episode of Discovery, we hear the Klingon speaking in Klingon with subtitles and once the UT is activated we hear them in English (or whatever human languages is the dub), the Klingon even says “I did not expected you to speak Klingon” and Michael says it is the translator. This would also explain why a Japanese heard people speaking in Japanese in “The 37” and how Picard and Data are capable of going undercover as Romulans into Romulus itself. You don’t really hear anything over the other person’s voice, you hear the person’s voice in your language because the trick is that your brain itself changes the meaning inside your head.

Of course, this doesn’t explains the lip-sync, technically that should still be an issue. But everyone who has seen a dubbed movie (and I don’t mean the terrible bad old times dub of Asian martial art films, but the careful quality dubbing you can see in Western media like between Spanish, English and French) your mind ignores the lack of sync. I guess it could be handwave that unless the language is too different and it takes you a lot of time to say one word your mind just overlooks the lack of sync like watching a dubbed film.