All plugins are DLLs, which are
coded in C++. So, in order to create a plugin, you should know
how to code in C++. You also have to follow the required architecture
(as defined in this SDK).
Note: You may be able to code the DLL in
something else other than C++, but the engine is designed to work
with C++ (MSVC++, although other compilers may and probably will
work).