Obviously, speaking several languages comes in handy in Europe, but in the USA, most people get along fine speaking English only. What benefits would an American who doesn't travel abroad get from learning another language?
In America, Spanish is fast becoming THE second language - simply because there are so many hispanic people there. We are after all, neighbors with Latin America. In Miami, where I am from, Key West is a mere 90 miles from Cuba and Miami is a point many of them chose to flee to. Indeed, many jobs in Miami require you to be bilingual.
Here in California, in addition to Spanish, Chinese (Mandarin) or Japanese would be invaluable. Many jobs here who do business with Asia are requesting bilingual workers.
When I lived in New England (New Hampshire to be specific) we even had a French Language channel that came with basic cable. You guessed it... our neighbors to the north spoke French.
We don't have to travel abroad to encounter situations where speaking another language comes in handy.
Supposedly there's a strong French influence in New England. I say supposedly because that's what I've heard, but I never ventured into New England before (despite the fact that from my home on Long Island, I lived 17 miles away from Bridgeport, Connecticut... of course the Long Island Sound is a barrier, I never did take the ferry over)
Knowing another language has so many benefits even within the United States. I agree with everything Tiffany said. Even if you never leave, you'll certainly eventually find use for it somewhere. Plus it's a huge personal accomplishment, no matter what language you learn, and it certainly is a testament to hard work and dedication.
Contrary to popular belief, English is not the only language spoken in North America. Maybe if you learned Spanish or French you would feel more comfortable travelling and would perhaps experience a different culture and gain some well needed respect for those other cultures. Maybe even gain a non ego-centric view on the world.
I'm not saying that all Americans are ego centric, but I would say that anyone who would pose the above question maybe is.
Yet another point: knowing (an)other language(s) can help you understand and appreciate your own, especially when you speak a language that has drawn as much from other languages as English has.
I think that all of us who communicate on this web site are linguists of some type and love languages. Therefore, we are not going to readily slam multilingualism.
Looking at it objectively, though, multilingualism has its pluses and minuses. It does give you insights into how people of other nationalities think and feel which a monolingual newsman will never acquire, even if he visits their country and you don't. There is also some truth in that Czech proverb that "He who knows four languages is four times a human being".
The downside of multilingualism, however, is that it can cause political problems in a country. I still remember newspaper reports from 1958 about riots in Belgium over language (French vs Flemish) and how it divided people there. Part of India's problem has been the lack of a unifying language. Recently, on a tv news report about more jobs in the U.S. preferring someone who knows Spanish I heard an American man respond angrily: "That's not right. I'm not going to be a second class citizen in my own country because I don't know Spanish!" So, we have to be mindful of the political ramifications of multilingualism too.
Brennus said: >>The downside of multilingualism, however, is that it can cause political problems in a country.<<
I can confirm this is true, being from Eastern Europe I know there are a lot of problems with two language communities living side by side, both on a local and on state level. But is multilingualism to be blamed for this? I think the problems do not have to do with being multilingual, but with social factors and lack of tolerance, indeed, with human nature itself. Wherever more language communities exist side by side, one of them will always try to gain the upper hand. One way (perhaps the most effective) of coping with this is the model of positive discrimination applied in Finland (even the Finnish majority has to learn the language of the Swedish minority at school) and in Switzerland (the majority language of a given area is given priority in that area, be it German, French or Italian, and Rhaeto-Romanic is also an official language, although it is spoken by one per cent of the population).
>>There is also some truth in that Czech proverb that "He who knows four languages is four times a human being".<<
We also have much the same proverb in Hungary, it sounds something like this: "As many languages you speak, so many times a human you are".
Just to add something to my above post on multilingualism: in former Yugoslavia there was a policy similar to that in Finland, the ethnic Hungarian pupils, including myself, learnt Serbian (the majority language) at school, and Serbian pupils also had Hungarian classes. As a result, there was much less inter-ethnic tension than there is nowadays, when all this has been abandoned, and pupils speaking one language are not given a chance to know the language and culture of the other community. Also, mixed friendships are less likely now than they used to be when I was at school. Of course this is more complex than just knowing a language, but still...
In many cases, learning another language also helps you understand your own language better. I grew up speaking French and English and both of those languages were ingrained in me so early that I never had the chance to think about why the languages worked the way they did.
It wasn't until I started studying Latin in university that I really thought about things like sentence structure, tenses, etc. It was also interesting to be able to pick out root words and to see how seemingly different words were actually related. I also know people who have studied French and have said that I helped them understand English better.
>> but in the USA, most people get along fine speaking English only. What benefits would an American who doesn't travel abroad get from learning another language? <<
Hey, why stop here? You might as well have asked something like, "Why travel at all?"
"As many languages you speak, so many times a human you are".
We have exactly the same proverb.