 Individual machine languages are specific to a family of processors; machine-language code for one family of processors cannot run directly on processors in another family unless the processors in question have additional hardware to support it (for example, DEC VAX processors included a PDP-11 compatibility mode).They are (essentially) always defined by the CPU developer, not by 3rd parties.The symbolic version, the processor's assembly language, is also defined by the developer, in most cases.