One thing I LOVE about C is that it's so easy to create APIs that other languages can use. For instance, if a C library exposes a good API, you can call it from lisp quite easily with CFFI. This gives you a large advantage: the low level, raw speed of a C library paired with the high-level forms of whatever language you choose.

I'm all for people writing programs/apps in C++, but I kind of cringe when I see a library in C++ because it's a harder language to wrap around.