According to an article from the Deutsche Welle, the European Court just made it easier for those who don't speak German (well) to study in Germany. The European Court has decided:
Wenn Ausländer aus Nicht-EU-Staaten in Deutschland studieren wollen, müssen sie bestimmte Zulassungsbedingungen erfüllen. Sie brauchen gültige Passpapiere und eine Krankenversicherung, sie müssen an einer Hochschule zugelassen sein und für die Kosten ihres Aufenthaltes selbst aufkommen können. Außerdem dürfen sie keine Bedrohung für die öffentliche Ordnung, Sicherheit oder Gesundheit darstellen.
Roughly translated:
When foreign nationals (outside of the EU) want to study in Germany, they must meet certain requirements: a valid passport, health insurance, acceptance to a college, and be able to financially support themselves for the duration of their stay. They must also present no risk for public safety or health.
Thus students are not required to be fully fluent in German or to have passed a basic German test to be able to study in Germany.
It's always a good idea to learn some of the language before you visit another country and if you're going to study in another country, all the more. However this breaks down one hurdle for students who have a chance to study in Germany and to work on a fantastic education, but don't have the possibility to learn German wherever they are now.