The United States debt to China and others is growing every day. We are only able to pay the interest due to the printing of more money. We can never stop printing money because we would not be able to pay the interest on the money we owe. The dollar is depreciating at an alarming rate. Russia and China will probably no longer trade in dollars. Soon groceries will be too expensive for the average family. We have an uncertain future.
Not to joke around, but sooner or later America will fail. With the national and international debt rising America will have to file for bankruptcy. America will have to be sold off piece by piece to pay off this massive debt. Some Americans might even be sold into slavery. Do not underestimate the value of a human life in terms of labor. We probably will end up learning Chinese in the distant future. If not all of us, some of us.
I highly doubt Americans will ever, as an entirety, need to learn Chinese as a necessity. It would be rare to find people who have learned Chinese now, because it's not something that is likely to be used in the future, unlike Spanish or even French, which will undoubtedly be very useful to know in America.
The chances of American citizens needing to learn Chinese on a large scale is not likely. Obviously, those who have the interest to work with those who only speak Chinese will need to learn the respective language, but the chances of any foreign language being required to be spoken by 'all' Americans is unlikely.
American will never have to learn Chinese. If we choose to do so, we will have the option, but it will never be required. America is a completely separate country that has a variety of languages. The only way I could see this happen is if we are taken over by China, which is unlikely.