C Programming Language was originally developed by Dennis Ritchie in Bell Laboratories for the purpose of implementing the UNIX operating system. Later American National Standards Institute or ANSI standardized the definition of C.
The language has fairly small feature set, which makes it easier to define it in small space (beneficial for embedded systems). However, most standard implementations include standard libraries with functions such as handling input/output.
It is considered a very mature language with stable compilers available for all standard platforms (both free and non-free). Linux kernel and many other kernels are written in C. A lot of high-level languages are also implemented in C.
GNU Compiler Collection or GCC includes a standard open-source C compiler, which is easily available on most Linux distributions.