If they have all nationalities within the US soil, don't need need visas to visit most countries, and they can use credit cards to finance their trips or education?
Although most Americans have to learn at least 2 years of a foreign language in school, it is not required for most higher-level degrees, and not considered very important for some jobs. Also, English is the international business language, and many Americans believe that they can travel anywhere and speak English, and everyone will understand them. While you and I and the rest of the world know that this is not true, many in the states believe this.
I would mention, however, that many Americans on the southern border can either speak or understand Spanish, due to a higher concentration of Spanish-speaking people who live there or nearby.
I'd also mention that many Americans either don't travel outside of the USA very often (our own country is very big and full of things to see), or like to travel to resort-style areas that cater to Americans/English speakers when they do, so the need to learn fluency in a second language is not high.
Finally, I'd also like to mention that most immigrant families (my own included) feel the need to speak English in order to assimilate when they arrive. My family dropped Italian almost immediately upon arriving, and I never got to learn Italian growing up because of it.
I don't agree with it, and currently am learning my third language while living in country number 4. America is a very large place, so it's hard to say what the motivation for 'Americans' is or isn't, because there are many people and with that comes many reasons. I hope this answer is helpful!
I sort feel like the same problem arises wherever you go though. I mean obviously, Anglo-saxons don't really feel the need to learn other languages because theirs is so prevalant, but even in France, where I'm from, you;d be shocked by the number of people who can't understand the simplest english.
It's just a question of convenience. If you weren't born in a family that doesn't speak the language of the country you live in then "what's the point" right?
It's an Anglosphere "problem"! Most people in Australia are only capable of speaking English and if you have learnt another to a reasonable degree, you're a wunderkind. Similarly, the UK is notorious among the nations of Europe for being worst at foreign languages. I guess it just has to do with the fact that the global lingua franca (at the moment) is English and thus, there is no urgency/motivation for Anglophones to learn other languages. This is changing though; the economic rise of China has also seen numbers of Mandarin learners (not just from Anglophone countries) sky-rocket!
I don't speak for most Americans, but from my short period here on earth it simply comes down to being lazy, and or not exactly essential. This is basically the same thing as why the USA has not adapted the metrics system. Once someone learns something, they tend to become resistant to change. We sell Milk and Gas in Gallons, not liters. Yet, alcohol and soda are sold in liters.
The United States does not even have a offical language. The French of course have French, Germany has German, but one might assume the USA would be English, but we do not have one. People just speak whatever language they choose too.
See, my family came here from Europe. My father and his family spoke about 6-7 languages, because in Europe all of the countries are close together. Europe is like the United States, with each EU being a different state... In Europe you can hop on a train and visit another country and have a real need to learn another language. In the USA that need does not really exist.
Do people buy umbrella's when it is not raining? Rarely, however, when it poors, there is a huge demand for it and in some ways it becomes necessary. As more people in the USA are speaking spanish, there becomes a bigger demand to learn the langauge, so now more than ever a lot of people are starting to learn the language. If they refuse, some may have a harder time getting job placement.
Agree with several of the posters here.
First, the way we teach languages is just stupid. We wait far too long, then it's too little - too late - with the wrong teaching methods. We don't start until high school in most places, then it's only available for the "college prep" kids. Budget cuts have left many public school districts without any language instruction at all.
Second, there's not a lot of pull. Only 40% of Americans have a passport, and some estimates show that only 5% travel overseas in a given year. Many have never left the States at all - even fewer have been outside the US, Canada and Mexico. Aside from Spanish in some areas, there is no regular exposure to other languages. People who come to America are expected to learn English.
Then even when we do travel abroad, we can go anywhere and most of the staff people we encounter speak great English - partially because that's where we choose to go. It's not until we go off the main tourist routes and get away from business centers where we find people who literally cannot talk to us. So it's easy to start assuming that someone will speak English anywhere, so why bother? I have to admit that I've fallen into that trap myself, at times.
Finally, it's so easy to fall into the trap of failing to capitalize on opportunities to practice. For most Americans, a second language is a luxury. For many others around the world, English is a basic survival skill, at least if you want to prosper in business. Therefore, anyone I encounter in a professional setting is likely to speak better English than I speak of their native language, and so it's just easier to use English.