Many non-English-language countries end up with most people who've been through higher education knowing at least some English, not only so they can handle sources but also so they can talk internationally to any other country as well as consume American media.

It's also a status symbol.

The smaller the language pool is the stronger this effect is. Japan is large enough that it's less guaranteed. Places like India and Indonesia that have a lot of internal languages end up using English as a lingua franca (+) as well.

(+) latin term!