I was running into a problem in CS6 with my text tool – the quotation marks were messed up. The opening mark was laying right on the path line, and the closing mark was confused and looked like the opening one. But, I reset the preferences and the problem went away.
It sounds like you changed your text language to German. The Smart Quotes feature automatically matches the quotation marks character to whatever is appropriate for the language in question. From what you're describing, that's German. Resetting the Character Panel or trashing your preferences will restore it to the language of your installation, most likely English.