How to always insert single and double quotes? Whenever I try to insert " or ' I have to validate it by space, otherwise strange things happen as with ' followed by an a becomes áinstead of just 'a, similar behaviour with double quotes. I find this annoying and want to disable it. How do I do that?
The problem lies in your keyboard layout which uses 'dead keys', probably your keyboard layout is US International.

Go to System Preferences -> Language and Text -> Input Sources and choose another layout, such as US Extended.