The US doesn’t have a national language, but does have significant communities of many ethnicities. It is well recognized that a second language is beneficial and I have to assume most states require it, although my experience there is limited. However it’s not reasonable to mandate that everyone learn a specific one. You should learn the one specific to your circumstances.

That being said, most people have no reason to actually use the language they learned in school so are never fluent or lose it quickly. It’s a newer thing for schools to offer immersion programs to establish fluency