German Language

If you wanna live here its very important to know the language

Most Germans do understand English to a certain extend, although few are comfortable enough to use it on social or professional occasions.
That means: It is very well possible to SURVIVE here without speaking German (you will be able to buy everything you need, ask for directions and all other aspects of daily life), BUT your social life will be limited AND it will be very difficult to find a job without speaking the language.
I hope this answers your question.

I agree with beppi, most Germans do speak English to a certain degree but living here with only English would be somewhat of a half-life.
Personally I found attending a language school helpful in improving my language skills and I attend a school called Sprachenatelier in Berlin ( https://www.sprachenatelier-berlin.de/en)
Aside from learning in a formal environment in the school, I also try to watch something in German every day (Tv, Youtube etc) and read something. It also sounds a bit rude- but I try to listen into conversations on public transport to hear how natives interact with each other and pick up some new words and phrases.
Best of luck to you x