this is how i change my fonts, no scripting etc needed.
You can use a mod to change in game fonts. Or you can replace the original game fonts with the fonts you want to use. Create the following folder:
<WoW directory>\Fonts\
Create copies of the font file of your choice, place them in the above folder, and rename them to the following names:
FRIZQT__.ttf (the main UI font - NPC names, player names, spell names, item names, buffs, quest log text, combat text, button text)
ARIALN.ttf (chat font, info text, small text)
skurri.ttf (default unit frame combat text)
MORPHEUS.ttf (mail text, quest log header text)
FRIENDS.ttf (friends list text)
http://vranx.com/font.htm
not 100% sure if it works with elvui aswell since i never use it
hope it help