Actually you are incorrect. :p

GSC is a script language that call of duty uses instead of having to write all of their stuff in other languages they basically made their own.

SPRX is not a language. However it is an executable which is ran by the eboot. The eboot must contain an execution of it though. A default eboot or debug eboot does not contain an execution of the SPRX. SPRX stands for Signed PPU Relocatable Executable. Basically in an SPRX you write it in C++ which you tell it to create a new PPU thread on the system. Tnen your code runs via that. In return of running internal code you can easily reference and edit memory.

Taylor you should know better sprx is a plugin :p