Or, a device that can translate languages on the fly, so that we can travel to foreign countries and not have to bother learning another language to converse with the locals.

That will obviously require a very sophisticated A.I. So much has to be gathered from non-linguistic context: tone of voice, facial expression, body language, visible referents, the latest news topics, the speaker's profession, etc. Translation of written language will be available first because most of these contextual factors are absent.

I'm sure that the first primitive software will be available within 10-20 years. It will be a project like Windows, managed by salesvermin instead of engineers, so it will be just as crappy as Windows. However, I wouldn't be surprised if affordable, really decent written-language software were already on the market by then.

Bear in mind that there will never be true real-time translation a la Star Trek. Languages differ in structure and you often have to wait until the very end of a sentence in the source language before you can fill some of the first words in the sentence in the target language. Everyone who's studied German has been frustrated by nested Schachtelsätzen, and by infinitives that only reveal the action performed in the last word of the sentence. Chinese has no tense or number, so you really need to stay in touch with the context to know whether to translate something in present or past, singular or plural. Japanese is full of "zentences" like "a kick occurred," leaving you to rely on the cultural background that you of course spent half of your life learning to figure out who would have dared to kick whom. Going the other way, from English to Japanese, verbs are conjugated by relative social standing so you have to think outside of your egalitarian box and keep track of the speaker's relationship to his audience.

Yuk. O.K., how about just English to Italian and back? Just translate the spoken word, no body language.

Possible, but it would slow down conversations by a small amount that's unacceptable in some conversations (like "That man stole my money! He's getting away!" to a police officer). I think it's just best to learn languages anyways.

Just learn the damn language will you. At least learn some basic conversational sentences and response before you visit a foreign language country. Seriously how awkward having to always carry a notebook just to converse with people.

That said it would be nice if we can jack into each other's brain to converse and understand each other with automatic language translation though. Maybe something like in Ghost In The Shell...

Feh, we each think in our own language (although it comes out in the spoken language you're trying to think in), so although emotions could be translatable, at best only twins could use it for any practical purpose. At worst, you'd have to learn a new language anyways.

Well there are various PDA type language translators you can get however they currently don't utilise verbal translation.

The problem with verbal language, the various languages and their dialects is not everything is straight forwards. If my sentences here were put through a language converter for a foreigner who didn't understand English Syntax they would find it's jumbled mess of unstructured words disjointing from being a sentence to say the least. (Some might even consider my sentences confusing enough even in English)

This is why a "Babelfish" or on the fly Verbal translator would require a vast amount of processing power since it's not just translating the words themselves as the problem but their syntax too.

Not if you're fluent in another language - then you can think in that language.

No, what I mean is that our brains each have their own 'language.' Programming might be more appropriate. Jacking into each other's brains wouldn't work because even if my dad and I did it, it'd be like we were trying to communicate in different languages.

Evidence?
I've already indicated that it's possible to think in a language other than your native one, so what language do we think in?
A universal "mind language" that is then translated into what we call our native language to speak?

Well if our brain truely go cyber one day and can be jacked into each other then whats to say we can't just install language programs. I can't see why not no!?

"Farscape" had an interesting variation on this. They injected Translator Microbes into everyone's brain. They never talked about it (bless those writers, the characters didn't walk down the hall casually discussing how everyday appliances work like the folks on Star Trek do) but it seemed to be a two step process. My microbes pluck out the organized thoughts in my speech center and translate them into an intermediate language that my mouth forms and the other microbes hear, while I hear myself speaking English. Then the microbes in each listener's brain translate them a second time, so each of them hears his native tongue.

There's a certain practicality about that from both an engineering and a linguistic standpoint. (Bless those writers again.) On Star Trek each Universal Translator works both ways so that only one party in a conversation needs it. The person wearing it hears his own native language but his mouth speaks in the listener's. That never made sense to me for a lot of reasons. What if you're talking to a polyglot audience? And on the single occasion that we got to see Quark's nephew pull out a U.T. and repair it with a hairpin (apparently the most important tool ever invented by mankind ), we learned that it is worn in one ear only!