A programming language is a formal language that specifies a set of guidelines that can be utilized to deliver different types of output. Programming languages generally consist of instructions for a computer. Programmers use programming languagae to develop software programs, scripts, or other sets of instructions for computers to execute.
From the early 1800s, "programs" were used to direct the behavior of machines such as Jacquard looms and player pianos. Thousands of different programming languages have been created, mainly in the computer field, and many more still are being created every year. Many programming languages require computation to be specified in an imperative form while other languages use other forms of program specification such as the declarative form.
The description of a programming language is usually split into the two components of syntax form and semantics meaning. Some languages are defined by a specification document , the C programming language is specified by an ISO Standard while other languages such as Perl have a dominant implementation that is treated as a reference. Some languages have both, with the basic language defined by a standard and extensions taken from the dominant implementation being common.