Language is actually a vocabulary and set of grammatical rules for constructing a computer program to perform a specific task.
The term programming language usually constitutes several set of instructions to perform a specific task. A program is written as a series of human understandable computer instructions that can be read by compiler and linker, and translated into machine code so that a computer can understand and run it.
Thus we can say that a programming language is a computer language, programmers used these languages to develop applications, script or other set of instruction for a computer to execute.
Such instructions can be executed directly when they are in the computer manufacturer-specific numerical form known as machine language, after simple substitution process when expressed in a corresponding assembly language, or after translation from some higher-level language. Although there are over 2000 computer languages, relatively few are widely used.
Machine and assembly languages are low-level, requiring a programmer to manage explicitly all of a computer's idiosyncratic features of data storage and operation. In contrast high-level languages shield a programmer from worrying about such considerations and provide a notation that in more easily written and read by programmers.