No, you really don't. You only need to know English if you're selling to English speaking people. You'll probably need to learn English for a number of professions. But apart from that you can live and work perfectly well without using English at all.
English isn't the main language on the Internet any more, it is just one of them. The fact that you happen to think that English is the major language used on the Internet is possibly just a vicious self-reinforcing cognitive bias.
It's not about the language of the internet, it's about the language in which the most influential books and papers are written. If you can't read ACM papers or IEEE specifications you're at a disadvantage whether or not you're selling to English speakers. If I were to build a car and the best resources were written in Japanese I'd be at a disadvantage even if I was working for, say, a Swedish outfit.
Since most researchers relocate in the states and subsequently publish their findings in English there's no doubt that the best sources of knowledge are written in English.
No, you really don't. You only need to know English if you're selling to English speaking people. You'll probably need to learn English for a number of professions. But apart from that you can live and work perfectly well without using English at all.
English isn't the main language on the Internet any more, it is just one of them. The fact that you happen to think that English is the major language used on the Internet is possibly just a vicious self-reinforcing cognitive bias.