Оригинален текст - Английски - I know a little about a lot (of things), but not...

Hi there! :) This sentence is kind of the "motto" of a friend of mine. I want to design him an Ex Libris for his birthday, and thought it'd be great to have that one it in Latin. The problem is that his birthday is already on the 22nd, so I don't know if there's enough time to have it translated here...anyway, can't hurt to check. :) Thanks very much in advance!
-Rebekka