In most big tech companies worldwide English is a work language. Even, for example, in Google offices in Germany or Japan everyday interaction and most of the work happens in English. This way, people from other countries can move and work there as long as they know English well.
Almost all interviews are also in English too. Therefore, it's important to know English well enough to confidently understand it and speak with other people.
If you are not a native English speaker, learning the language well may take years, so start early. Here are some more tips for getting your English better for the interviews:
- In the interviews, you are expected to understand everything that's written, and most of what's being told. You are not expected to have a perfect prononcuation or vocabulary, but you should be able to clearly explain your thought process and your solution.
- The best way to get your English better long term is probably just to go to some English learning courses. There are a lot of these in most cities nowadays, but because it will take quite some time, you are better off starting earlier.
- Get used to using English everyday. Switch your phone and computer to English, google and read everything in English (content in English is usually the best anyways), watch videos on YouTube, movies and tv shows in English with subtitles. This way you will automatically pick up a lot of the language.
- Even if your English is good, speaking with somebody in English in real time can be intimidating if you are not used to it. Speak in English as much as possible, even if just with friends. You can also do some mock interviews in English on Pramp with strangers from all over the world. This should help you a lot with understanding and speaking English, as well as with the interview skills.