I thought of changing the voice to whispering or shouting by switching between given voices, maybe using 2 voices at once and mix them per loudness.

Thanks for the links. I will have a look.

I'm astonished that I missed that one by peacekeeper. Great link! Didn't test it, though.

http://www.puppenheim.org/
http://www.wuerfels-welt.de
Old Game Tutorial: http://www.puppenheim.org/MITutorial.zip
Free Game Editor: http://puppenheim.org/AlienalsWeihnachtsmann.zip
http://www.puppenheim.org/blender_starting_main_settings.txt