Sets of Skyrim is a phenomenal class system mod by Robin959. The mod aims to fix spelling errors and provide consistent styling the various menus. Words have been standardized to American English spelling, and styling generally aims to match vanilla Skyrim. Some examples of fixes included are:

-Capitalization of all classes in UI selection menu.
-Standard punctuation in all descriptions.
-Standard bolding of numbers but not % signs in all menus.
-Spelling errors displayed in game fixed throughout, including in scripts which have been recompiled when needed.
-Styling of perk descriptions to be consistent with: Benefit, under which conditions it applies, and then duration.

Installation:
Install with a mod manager
Load after Sets Of Skills. 
Be sure to install all requirements for Sets of Skills.

Compatibility:
Load immediately after Sets of Skills.
Load before Sets of Skills - Custom Skills Framework. Download the compatibility patch and load after SOS-CSF
Load before Sets of Skills - MCM Setting Loader.
Let any other Sets of Skills mod overwrite this patch.
If something else modifies Sets of Skills this will probably need to be patched. 

FAQ:
Why not British English?
-I am not British.

You missed something!
-Darn! Tell me nicely and I'll fix it.

Something is inconsistent!
-See above.

Thanks to:
Robin959 for the great mod and open perms
Lively for Tempus Maledictum
England for the English language