[joe_the_user]

Is the concept of using 2 languages at the same time so scary?

In all honesty, yes.

But consider this also. The advantage of C++, such as it is, is that the big, harry objects you are creating can call each with just about any calling conventions you chose and you can parameterize them at run time and compile time in whatever crazy way you'd like (pointers, templates, static objects, classes and ponies! (Ponies will only be standardized in C++_2015)). This is why Python, Lua and all each call c/c++ for extensions. But while there are many interesting scripting languages out there, there's no guarantee that any of these languages' calling convention, memory usage and constraints will be what your large objects need. Specifically, to effectively use a particular higher-level language you'd have to know from the beginning that said language's conventions would satisfy your needs from beginning to end.

Add to this the fact that C++ may not be a "good" programming language but that it's not that bad if used with discipline and understanding. The badness of c++ comes from the many, many ways you can shoot yourself in the foot - it still doesn't force to do anything. But how many subtle bugs can creep in if you're sloppy in passing raw pointers to some other language? And using any higher level language will involve forcing yourself to do a number of things that could prove problematic.