There are many "computer languages" that could be described. However, one thing they all have in common is that none is a spoken language capable of expressing the complex and abstract concepts human beings are capable of. A computer "language" is a formal system with a fixed vocabulary of terms, a small number of well-defined syntax rules (specifying how terms may be ordered), and unambiguous semantics (set of rules for expressing meaning).

The earliest computer language was machine language, the language defined by the instruction set of a computer's central processing unit (CPU). A computer's instruction set consists of the sequences of bits that control what actually happens in the CPU. Machine language is machine-dependent--different for every computer--and very hard for humans to work with. It is the lowest level of abstraction possible, and is thus the lowest-level language. Nonetheless, early programmers had to write their...