The original PSP Fonts that came with and were distributed with the Portable Console, are not legal to include with the PPSSPP Emulator!
The drawback to this is that "many" games suffer as a result.  Included in the PSP FONTS.7z are over 100 Custom PSP FONTS you can easily
install using the km_PPSSPP Custom Fonts HMOD.  

Simply copy the pertinent ltn0.pgf you choose to 
use into the root font folder, and make sure to
install this HMOD after PPSSPP Core! 
To revert 
fonts, uninstall then reinstall PPSSPP Core.  Or, 
you can reinstall this specific HMOD, pre-ltn0.pgf
replacement.  You can,
of course, use the "original" PSP Font, as well!

Symptom of using non-system specific, "original" font, would typically be Fonts are too wide / wrong size in some games compared to
original system.  Examples of games affected by this, to varying degrees, are:

Crush
Dissidia
Exit
Fieldrunners
Final Fantasy 3
God Eater Burst 1/2 *
Gundam vs. Gundam Next Plus
.hack//Link
Holy Invasion of Privacy, Badman
Jeanne d'Arc
Lord or Arcana / Apolcalypse
Lunar
Mad Blocker Alpha
Metal Gear Solid: Peace Walker
Monster Hunter games
Naruto Ultimate Ninja Heroes 3
Neverland Card Battles
Persona 3 Portable
Phantasy Star Portable 1/2
Ragnarok Tactics
Senjou no Valkyria 2/3 *
Sword Art Online
Tales of the Heroes: Twin Brave
Tales of the World: Radiant Mythology 1/2/3
Yu-Gi-Oh Tag Force games
**And, of course, several others:)

Font Set-Up is generally:

0 is Latin large
1 is Latin large with serifs
2 is Latin large in italics
3 is Latin large in italics with serifs
4 in Latin large in bold
5 in Latin large in bold with serifs
6 in Latin large in bold italic
7 in Latin large in bold italic with serifs
8-15 are the same again, but Latin small.

Suffice to say, it is generally best to be on the "original" PSP Font, if at all possible to be:)  But, there are some tremendously
awesome Custom PSP Fonts to play around with, too!

Sincerely, KMFDManic!!!

Personal thanks to Birdman1 and unknownbrackets and anyone else who helped in testing and information regarding the Font issues!