Prolog is a very different language to the ones above, mainly because it’s a logic programming language. That means that, unlike a lot of other languages that use procedural logic, Prolog is more about first-order logic, where the underlying logic of a program is expressed in various relations of facts and rules. Thus, the software works by interpreting queries according to these relations. Such an approach is why Prolog is mostly associated with artificial intelligence and NPL projects. 

Prolog is a logic programming language associated with artificial intelligence and computational linguistics.Prolog has its roots in first-order logic, a formal logic, and unlike many other programming languages, Prolog is intended primarily as a declarative programming language: the program logic is expressed in terms of relations, represented as facts and rules. A computation is initiated by running a query over these relations.The language was developed and implemented in Marseille, France, in 1972 by Alain Colmerauer with Philippe Roussel, based on Robert Kowalski's procedural interpretation of Horn clauses.Prolog was one of the first logic programming languages and remains the most popular such language today, with several free and commercial implementations available.