This issue is not a black and white speak english vs not kind of thing. There’s no shortage of immigrants that speak english perfectly well sans a minor accent but are discriminated against and treated poorly anyway for not being native speakers.
Edit for those who downvoted: I am a native english speaker. I have been discriminated against based on my regional accent. Only a fucking fool would think the same things don’t happen to nonnative speakers.
Operating System Concepts by Silberschatz, Galvin and Gagne is a classic OS textbook. Andrew Tanenbaum has some OS books too. I really liked his OS Design and Implementation book but I’m pretty sure that one is super outdated by now. I have not read his newer one but it is called Modern Operating Systems iirc.