This is a hiring issue, not a legal one. The US has no official language, and no language tests, so requiring English in law would be dicey to put it mildly. What if I'm hiring someone specifically to work at a Spanish language news outlet?
Second most visa applicants already get tested on their English skill when they apply for Visa, for example, universities require English proficiency for F1 visa using GRE exam
And why do you think you are better than an employer in assessing required English proficiency of an employee
Why would the universities fail them on these exams, when it would mean losing out on that sweet, sweet tuition money?
When the law specifically dictates stuff like the talent of the person, I’m not convinced you’re correct.
Congress would need to declare any official language(s). Moreover, by treaty and law (NALA of 1990) obligations to Native American tribes there must be more languages than merely English.
English test is a requirement for naturalization, which is governed by the same INA, which governs H1B and other visas.
Having actually worked at a Spanish language news outlet before (1 of 4 tv and radio stations in the office I was doing IT help desk work in), I can tell you that every single employee spoke English somewhere on the level of very good to near native fluency. As it turns out, knowing English (or the native language of whatever country you're in) is an incredible value-multiplier for almost every job position imaginable.
As far as language issues at my current job goes, it turns out once you hire a manager that speaks both Hindi and English (or Marathi and English, or Bengali and English, you get the picture) it doesn't matter much if the H1Bs he hires barely speak English because he can just start shouting at them in Hindi if they don't understand (even if several native English speakers are in the meeting too).