You know how on Star Trek all the alien species can talk to each other, even though they're from completely different planets and some of them have weird shapes on their foreheads?

That's because of the "universal translator," a technology that instantly translates speech so that both parties can understand each other, planet of origin notwithstanding.

It's a cool idea (unless you're a language instructor), but until recently it was just science fiction.

Well, next week NTT Docomo, Japan's biggest mobile phone network, is introducing a new service that will translate phone conversations in real time.

The tech, which is called Hanashite Hon'yaku ("speaker translation") analyzes the audio in the cloud and then submits the translated text to the other person after a slight delay.

Unlike the Star Trek version of the technology, though, this one will be pretty basic: it will translate Japanese speech to English, Chinese or Korean (and vice versa) and it probably won't be capable of handling much beyond basic conversation.

As well as working for phone calls, it can also be used in person.

The BBC's Richard Taylor reported on the app, and tested it. He spoke with a Japanese woman (his translator, in fact), and although it wasn't perfect, it just about got the idea across ("There is the restaurant of the Japan meal near").

Although it's not ready to handle complicated stuff yet, the possibilities for communication are huge if the technology can be improved.

What would happen to international business, for instance, if everyone could instantly be on the same page, language-wise? And collaborating on art projects, political initiatives, aid work... They could all get a lot easier all of a sudden.

Of course, NTT Docomo isn't the only company working on this stuff.

California-based MyLanguage provides voice and text translations during video chats with its Vocre app for iPhone, which offers similar real-time translation in a number of languages.

Google announced a basic speech-to-speech translation system for smart phones back in January, 2011 as part of its Google Translate app. At the moment, the app is in the "Alpha" stage, meaning it's not that smooth, but it works with 14 languages.

Microsoft Research Labs is working on what it calls the Translating Telephone, and Israeli start-up Lexifone launched earlier this year, offering over-the-phone automated translation via a special access number.

So lots of people are working on the idea, but not everyone's convinced it will succeed.

"These kinds of real-time technologies have been 'two to three years away' for the past decade," Benedict Evans, a technology expert at Enders Analysis, told the BBC.

"Both speech recognition and machine translation are sort of there if you're not too fussy. But they are generally not as good as speaking the language itself."

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