Do people speak good English? How hard do you think it would be for a foreigner (not speaking German) to get around in Berlin?
Consider the similar phrase, "Did you eat good pie", versus "Did you eat pie well". In the pie case the former is correct because you're referring to the quality of the pie. In the case at hand, we're talking about the quality of the speaking.
In short: working in the startup scene won't be a problem; grocery shopping might be an adventure. ;-)