Garr has written a lot about presentation design and fonts in his wonderful blog and also recommended Robin Williams’ The Non-Designer’s Design Book from which you can learn a lot about design in general and, indirectly, about presentation design. Today I made a “wordle” of “Es spricht!”. Although randomly (?) designed by an algorithm the outcome is very beautiful – and a great mixture of languages.
Here you can see that using one font in related colours can produce coherence and form inspite of being random.