Why are some fonts blank in my CS5 character panel?

Hi,

I'm wondering why some fonts arent visible in my character viewer. I am using Illustrator Version15.0.2 on a MacBook Pro running 10.9.1. I have included 2 screen shots below for a visual reference.

AND

Additionally, I'd like to understand how the fonts in the character viewer menu are organized. I know they are alphabetical, but what are the grey divider lines representing?

Can I deactivate non-english language fonts so that this menu is less conjested with fonts I never use? I've used Illustrator for years and am finally getting around to asking this question. I can't seem to find a straight forward answer regarding which fonts are actually non-english. As a side note, I use Font Explorer X Pro to manage my fonts.

Thanks for any insight into this.