One of the most widely recognised programming languages in the world. C, was written by K&R to write their portable OperatingSystem in which they called Unix. C was originally derived from BCPL, however it has evolved radically from it's predecessor. Often described as a portable assembler. C is a great systems language, but is blamed for many problems with applications which many complain it is unsuited for. C has inspired an entire class of languages, including C++ which some say fixes many problems with C, while others debate is just a horrible mess. Java has decended from C++ as a portable, clean object orientated language, and which in turn is the father for CSharp Microsofts new language.

I recommend you learn C, and use it for writing OperatingSystems?, and understanding how things actually are implemented, but then code in some other programming language if you are going to write applications, especially networking programs.