To study in Germany, you need to prove that you speak English or German well enough to study in that language. This proof needs to be delivered by handing in an official language certificate, unless you are a native speaker or have graduated from an English or German speaking program.
Of course, getting to this point requires hard work. But do not worry: Universities will not expect you to speak anywhere near as perfectly as a native speaker.
More than 245.000 international students are currently enrolled at German universities, most of them come from non-English and non-German speaking countries. Therefore, universities in Germany are prepared to have second-language speakers in the classroom.
Even some of your professors will speak with accents, especially if you study in an English-taught international program. So as soon as you reach the required level, do not be afraid that you do not speak enough English or German. You will have to invest some time and effort, but the language level required from you is fair and reachable.
Even if you have never been to an English or German-speaking country and feel like you are not as much of an expert as you would like to be – YET!